Abundance of selected genes implicated in testicular functions in Camelus dromedarius with high and low epididymal semen quality

Studying testicular genes' expression may give key insights into precise regulation of its functions that influence epididymal sperm quality. The current study aimed to investigate the abundance of candidate genes involved in the regulation of testicular functions specially those regulate sperm function (PLA2G4D, SPP1, and CLUAP1), testicular steroidogenic function (ESR1 and AR), materials transport (AQP12B and LCN15), and defense mechanisms (DEFB110, GPX5, SOCS3, and IL6). Therefore, blood samples and testes with epididymis were collected from mature middle-aged (5-10 years) dromedary camels (n = 45) directly prior and after their slaughtering, respectively, during breeding season. Sera were evaluated for testosterone level and testicular biometry was measured with caliper. The epididymal tail semen was evaluated manually. Samples were distinguished based on testosterone level, testicular biometry, as well as epididymal semen features into high and low fertile groups. Total RNA was isolated from testicular tissues and gene expression was done using Quantitative Reverse Transcription Polymerase Chain Reaction (qRT-PCR). Results revealed that testosterone levels were significantly (P < 0.005) higher in camels with good semen quality than those of low quality. There was a significant (P < 0.0001) increase in testicular weight, length, width, thickness, and volume in high fertile than low fertile camels. PLA2G4D, SPP1, CLUAP1, ESR1, AR, AQP12B, LCN15, DEFB110, GPX5, and SOCS3 genes were upregulated (P < 0.001), and IL6 gene was downregulated (P < 0.01) in the testes of high fertile camels compared to the low fertile one. Thus, it could be concluded that examined genes might be valuable monitors of testicular functional status and fertility in dromedary camels.

Biphasic MERS-CoV Incidence in Nomadic Dromedaries with Putative Transmission to Humans, Kenya, 2022-2023

Middle East respiratory syndrome coronavirus (MERS-CoV) is endemic in dromedaries in Africa, but camel-to-human transmission is limited. Sustained 12-month sampling of dromedaries in a Kenya abattoir hub showed biphasic MERS-CoV incidence; peak detections occurred in October 2022 and February 2023. Dromedary-exposed abattoir workers (7/48) had serologic signs of previous MERS-CoV exposure.

Determination of breeding criteria for gait proficiency in leisure riding and racing dromedary camels: a stepwise multivariate analysis of factors predicting overall biomechanical performance

To date, the biomechanical dynamics in camelids have not been addressed, although it might be a factor that can affect selection and breeding in this species. Therefore, the aim of this article is to conduct curve fitting and discriminant canonical analysis to identify the mathematical function that best captures the dynamics of camel locomotion and to study the impact of kinematic, morphometric, physiological, and phaneroptic variables on gait performance in leisure riding and racing activities in dromedaries, respectively. The cubic function emerged as the most suitable mathematical model to represent the locomotive behavior of camels. Various factors were found to play a pivotal role in the athletic performance of leisure riding and racing dromedary camels. Concretely, angular measurements at the distal fore and rear extremity areas, pelvis inclination, relative volume of the hump, impact forces of the front limbs, post-neutering effects, and the kinematic behavior of the scapula, shoulder, carpus, hip, and foot are the factors that greatly impact gait performance in leisure riding and racing camels. The biomechanical performance at these specific body regions has a profound impact on weight absorption and minimization of mechanic impact during camel locomotion, static/dynamic balance, force distribution, energy of propulsion, movement direction and amplitude, and storage of elastic strain in leisure riding and racing dromedaries. In contrast, other animal- and environment-dependent factors do not exert significant influence on camel gait performance, which can be attributed to species-specific, inherited adaptations developed in response to desert conditions, including the pacing gait, broad foot pads, and energy-efficient movements. The outcomes of our functional data analysis can provide valuable insights for making informed breeding decisions aimed at enhancing animal functional performance in camel riding and racing activities. Furthermore, these findings can open avenues for exploring alternative applications, such as camel-assisted therapy.

Effects of long-term dehydration on stress markers, blood parameters, and tissue morphology in the dromedary camel (Camelus dromedarius)

Introduction

Dromedary camels robustly withstand dehydration, and the rough desert environment but the adaptation mechanisms are not well understood. One of these mechanisms is that the dromedary camel increases its body temperature to reduce the process of evaporative cooling during the hot weather. Stress in general, has deleterious effects in the body. In this study, we sought to determine the effects of dehydration and rehydration on stress parameters in the dromedary camels and how it pacifies these effects.

Methods

Nineteen male camels were randomly divided into control, dehydrated and rehydrated groups, and fed alfalfa hay ad-libitum. The dehydrated and rehydrated groups were water-restricted for 20 days after which the rehydrated camels were provided with water for 72 h. The control and dehydrated camels were slaughtered at day 20 from the start of experiment whereas the rehydrated group was killed 72 h later. Many biochemical, hematological histopathological parameters and gene analysis were performed in relevant tissues collected including blood, plasma, and tissues.

Results and discussion

It was observed that severely dehydrated camels lost body weight, passed very hard feces, few drops of concentrated urine, and were slightly stressed as reflected behaviorally by loss of appetite. Physiologically, the stress of dehydration elicited modulation of plasma stress hormones for water preservation and energy supply. Our results showed significant increase in cortisol, norepinephrine and dopamine, and significant decrease in epinephrine and serotonin. The significant increase in malondialdehyde was accompanied with significant increase in antioxidants (glutathione, retinol, thiamin, tocopherol) to provide tissue protection from oxidative stress. The physiological blood changes observed during dehydration serve different purposes and were quickly restored to normality by rehydration. The dehydrated/rehydrated camels showed reduced hump size and serous atrophy of perirenal and epicardial fat. The latter changes were accompanied by significantly increased expression of genes encoding proteins for energy production (ANGPTL4, ACSBG1) from fat and significantly decreased expression of genes (THRSP; FADS 1&2) encoding proteins enhancing energy expenditure. This process is vital for camel survival in the desert. Dehydration induced no major effects in the vital organs. Only minor degenerative changes were observed in hepatic and renal cells, physiological cardiomyocyte hypertrophy in heart and follicular hyperplasia in splenic but lipidosis was not depicted in liver hepatocytes. Ketone bodies were not smelled in urine, sweat and breathing of dehydrated animals supporting the previous finding that the ß hydroxybutyrate dehydrogenase, a key enzyme in ketone body formation, is low in the camel liver and rumen. Rehydration restored most of blood and tissues to normal or near normal. In conclusion, camels are adapted to combat dehydration stress and anorexia by increasing anti-stressors and modulating genes involved in fat metabolism.

Seroprevalence and risk factors of brucellosis in dromedary camels (Camelus dromedarius) in Sudan from 1980 to 2020: a systematic review and meta-analysis

Camel brucellosis is a major public health concern in Sudan; however, there is no overall estimation of the prevalence of camel brucellosis in Sudan. Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, this study aimed to perform a meta-analysis of 30 eligible studies published before December 31, 2022, with a total of 70059 dromedary camels, to estimate the pooled prevalence of camel brucellosis and its risk factors in Sudan. The random effect model was used for the final analysis due to the significantly high heterogeneity among the included studies, and the results showed that the overall pooled prevalence of camel brucellosis was 17%, with a confidence interval (CI) of 12%-21%. The prevalence was higher in males than females (54% vs. 46%) and in adults than youngling (77% vs. 23%). The prevalence also varied by region, with central and northern Sudan having the highest prevalence (24%), compared to other regions of Sudan. Moreover, the prevalence of camel brucellosis appeared to be decreasing over time. The current study concluded that camel brucellosis infection is still endemic in many areas of Sudan, with the disease being especially prevalent in central and northern Sudan. Thus, this study provides valuable information for the prevention and control of camel brucellosis in Sudan. However, the significant heterogeneity among the included studies should be taken into account when interpreting these results. Finally, to provide adequate information, research must be updated, and more research must be conducted in many regions of Sudan.

Mapping the branching pattern of the middle cerebral artery in the camel (Camelus dromedarius): a comprehensive anatomical analysis

The complex branching structure of the middle cerebral artery serves as a crucial component in the blood supply to the cerebral cortex, playing a key role in sustaining brain function and overall neurological health in mammals. A thorough understanding of the branching structure of the middle cerebral artery is required for the advancement of veterinary medicine and neuroscience research. In this study, we provide the first comprehensive anatomical analysis of the branching structure of the middle cerebral artery (MCA) in the dromedary brain. To date, no study has examined the MCA branches in dromedaries. By examining 80 cerebral hemispheres from freshly slaughtered male dromedary camels aged 2-6  years, we aimed to explain the origin, course, and branching patterns of the MCA in the dromedary camel. Advanced casting techniques using colored latex, epoxy paint, and liquid plastic have been used to create precise renderings of the MCA structure. Our findings revealed that the MCA is the principal branch of the rostral cerebral artery and serves as the primary blood supply to the telencephalon in dromedaries. The main trunk of the MCA splits into several cortical branches, each supplying blood to a specific cerebral hemisphere. These branches comprise the rostral and caudal olfactory arteries; orbital artery; superior, middle, and inferior frontal arteries; rostral, middle, and caudal parietal arteries; and dorsal, middle, and ventral temporal arteries. This groundbreaking work considerably advances our understanding of the dromedary cerebrovascular system by providing insightful information on the anatomy and topography of the MCA. Our findings open new avenues for advancements in veterinary medicine and neuroscience research, with potential applications in the diagnosis and treatment of neurological disorders in dromedary camels. Furthermore, understanding the unique branching pattern of the MCA may have implications for comparative neuroanatomy and the evolution of cerebrovascular systems across species.

Maxillary neoplasms in four dromedary camels

Four camels (Camelus dromedarius) presented to the Veterinary Teaching Hospital at King Faisal University with maxillary masses. On radiographs, the masses were multicystic and expanded the maxillary bone. The tumors were diagnosed by histopathologic examination as conventional ameloblastoma, two cases as intraosseous squamous cell carcinoma, and central odontogenic fibroma with ossification. To the authors' knowledge, this is the first report of ameloblastoma in a camel, the first detailed description of maxillary squamous cell carcinoma in camels, and the first report of central odontogenic fibroma in any animal species.

First detection of hepatitis E virus in dromedary camels from Iran

BACKGROUND

Hepatitis E virus (HEV) genotype 7 is a zoonotic disease detected in dromedary camels.

HYPOTHESIS/OBJECTIVES

The consumption of camel meat and dairy products, the abundance of dromedary camels in Southeast Iran and the import of camels from neighbouring countries to Iran made the researchers investigate the infection rate of camels by the virus.

ANIMALS

A total of 53 healthy camels in Southeast Iran (Sistan and Baluchistan Province) tested for HEV RNA.

METHOD

A total of 17 blood samples and 36 liver samples were taken from 53 healthy dromedary camels (aged between 2 and 10 years) from various southeastern regions of Iran. The samples were tested for HEV using RT-PCR.

RESULTS

Overall, 56.6% of the studied samples (n = 30) tested positive for HEV RNA.

CONCLUSIONS AND CLINICAL IMPORTANCE

The present study was the first of its kind in Iran and revealed the presence of HEV in the Iranian dromedary camel population, which might play the role of a zoonosis reservoir for its transmission to humans. This discovery raises concerns about food-borne illnesses that can be transmitted from animals to humans. However, further research is needed to identify the specific genotype of the HEV in Iranian dromedary camel infections and to determine the risk of spread to other animals and humans.

Pathological, microscopic, and molecular diagnosis of paratuberculosis/John's disease in naturally infected dromedary camel (Camelus dromedarius)

Background and Aim

Paratuberculosis (PTB) or John's disease is a chronic disease of ruminants impeding the reproduction and productivity of the livestock sector worldwide. Since there is a lack of pathological studies explaining the nature and development of the disease in camels, this study aimed to highlight the anatomopathological changes of PTB in camels, which may help in verifying and validating some diagnostic tests used to detect the etiology of the disease in camel tissues.

Materials and Methods

In August 2017, at Alselaa border's Veterinary Clinic of Al Dhafra Region, Western Abu Dhabi, UAE, one imported culled she-camel of 2 years old was subjected to clinical, microscopic, and anatomopathological investigations along with real-time quantitative polymerase chain reaction (q-PCR) to confirm the infection and correlate between clinical signs and pathological lesions of the PTB in dromedary camels.

Results

Clinically, typical clinical signs compliant with the pathognomonic gross and histologic lesions of PTB were seen in naturally infected dromedary camel. As presumptive diagnosis microscopically, acid-fast coccobacillus bacterium clumps were demonstrated in direct fecal smears as well as in scraped mucosal and crushed mesenteric lymph node films, and in histopathological sections prepared from a necropsied animal and stained by Ziehl-Neelsen stain. Free and intracellular acid-fast clump phagosomes were further confirmed as Mycobacterium avium subsp. paratuberculosis by q-PCR.

Conclusion

Clinical signs and pathological lesions of paratuberculosis in a dromedary camel were found to be similar to those of the other susceptible hosts.

Influences of glycine supplementation during vitrification on the developmental potential of vitrified/warmed immature dromedary camel oocytes

Oocytes experience detrimental osmotic stress during vitrification and warming procedures because of the osmolality imbalance between the vitrification-warming fluids and the intracellular environment. Cellular osmotic homeostasis can be preserved by glycine, a powerful osmolyte with antioxidant properties. We aimed to examine the influences of supplementing glycine to the vitrification solutions (VS) on the developmental potential of vitrified/warmed immature dromedary camel oocytes following IVM/IVF and in vitro embryo culture (IVC). Cumulus oocyte complexes (COCs) were collected from dromedary camel ovaries and randomly allocated into two groups namely control (oocytes subjected directly to IVM) and vitrified (COCs were vitrified into VS supplemented with 0.0, 0.5, 1.0 or 2.0 mM glycine). For vitrification, COCs were equilibrated for 3 min in 12.5% ethylene glycol; EG plus 12.5% dimethyl sulfoxide; DMS and then they were vitrified for 60 s in VS composed of 25% EG + 25% DMSO using solid surface vitrification (SSV). Warming of vitrified oocytes was conducted in decreasing concentrations of trehalose solution. Following vitrification and warming, the morphologically viable oocytes were subjected to IVM for 36 h. Matured oocytes were then fertilized in vitro by epididymal spermatozoa and cultured for seven days. The results showed that the percentage of viable oocytes assessed by trypan blue stain was significantly higher (p ≤ .05) in the 1.0 mM glycine-supplemented group than 0.0- and 2.0-mM glycine-supplemented ones (90.0 % vs. 80.0% and 76.6%, respectively). However, no significant difference was observed between 0.5 mM glycine and other vitrified groups. Nuclear maturation rates, cleavage (48-h post-insemination; pi) and blastocyst rate (7-days pi) were significantly lower in vitrified groups than control ones (p ≤ .05). Among vitrified groups, these parameters were the highest in the 1.0 mM glycine-supplemented group. Taken together, supplementation of vitrification solutions with 1.0 mM glycine could enhance the developmental potential of vitrified/warmed immature dromedary camel oocytes.

Immunomodulatory Effects of Bacterial Toll-like Receptor Ligands on the Phenotype and Function of Milk Immune Cells in Dromedary Camel

(1) Toll-like receptors (TLR) are a family of pattern recognition receptors that sense distinct molecular patterns of microbial origin. Although the immune cell composition of camel milk has been recently described, host-pathogen interaction studies in the camel mammary gland are still scarce. The present study aimed to use a whole milk stimulation assay for investigating the modulatory effect of selected Toll-like receptor (TLR) ligands on the phenotype and function of milk immune cells. (2) Methods-camel milk samples (n = 7) were stimulated in vitro with the TLR4 ligand LPS or the TLR2/1 ligand Pam3CSK4, and separated milk cells were evaluated for stimulation-induced shape change, the expression of cell surface markers, phagocytosis, apoptosis, ROS production, and NETosis. Stimulation with PMA was used as a control stimulation. (3) Results-all stimulants induced shape change in milk cells, change in the expression of several cell markers, and increased cell apoptosis and NETosis. In addition, stimulation with Pam3CSK4 and PMA was associated with enhanced ROS production, while only PMA stimulation resulted in enhanced bacterial phagocytosis by milk immune cells. (4) Conclusions-our data indicates selective modulating effects of the TLR ligands LPS and Pam3CSK4 on camel milk phagocytes. These results may have implications for the use of synthetic TLR agonists as immunomodulatory adjuvants of the immune response to intra-mammary vaccines against mastitis pathogens.

Open castration in dromedary camel through two scrotal incisions: A case report

Most of the time, castration is an elective procedure performed to make the camel docile and manage its behavior. There are also instances, where it is performed as a treatment of testicular abnormalities such as orchitis, irreparable traumatic injuries, and tumors. In the current study, a 7-year-old bull dromedary camel was brought to Addis Ababa University College of Veterinary Medicine and Agriculture, Feseha Gebre Ab VTH, with a history of recurrent swelling of the left testicle for a month. Based on history and clinical examination, the case was diagnosed as unilateral orchitis and admitted for open castration of both testes. Two percent lidocaine hydrochloride was injected into each testicle to provide a spermatic nerve block, and then, two parallel incisions were made through the scrotal skin on either side of the median raphe. The testicles were pulled out through these incisions, ligated, and transected. The scrotal incisions were left open to heal by themselves. Postoperatively, antibiotic and anti-inflammatory drugs were administered for 3 successive days. Finally, the camel was regularly followed for 1 week and recovers uneventfully.

Discovery of novel Mamastroviruses in Bactrian camels and dromedaries reveals complex recombination history

Virus emergence may occur through interspecies transmission and recombination of viruses coinfecting a host, with potential to pair novel and adaptive gene combinations. Camels are known to harbor diverse ribonucleic acid viruses with zoonotic and epizootic potential. Among them, astroviruses are of particular interest due to their cross-species transmission potential and endemicity in diverse host species, including humans. We conducted a molecular epidemiological survey of astroviruses in dromedaries from Saudi Arabia and Bactrian camels from Inner Mongolia, China. Herein, we deployed a hybrid sequencing approach coupling deep sequencing with rapid amplification of complementary deoxyribonucleic acid ends to characterize two novel Bactrian and eight dromedary camel astroviruses, including both partial and complete genomes. Our reported sequences expand the known diversity of dromedary camel astroviruses, highlighting potential recombination events among the astroviruses of camelids and other host species. In Bactrian camels, we detected partially conserved gene regions bearing resemblance to human astrovirus types 1, 4, and 8 although we were unable to recover complete reading frames from these samples. Continued surveillance of astroviruses in camelids, particularly Bactrian species and associated livestock, is highly recommended to identify patterns of cross-species transmission and to determine any epizootic threats and zoonotic risks posed to humans. Phylogenomic approaches are needed to investigate complex patterns of recombination among the astroviruses and to infer their evolutionary history across diverse host species.

Sex Differences in Fecal Microbiome Composition and Function of Dromedary Camels in Saudi Arabia

The gastrointestinal microbiome plays a significant role in diet digestion and the energy production of its host. Several factors that affect the gastrointestinal microbiota composition were studied in camels. Yet, the impact of sex on the gastrointestinal bacteriome of camels remains unexplored to date. In this perspective, the fecal microbiome community composition from dromedary camels was determined in 10 male and 10 female samples using the 16S rRNA amplicon, in order to estimate if this was influenced by sex. The core microbiome in females contained 284 bacterial OTUs and one archaeal OUT, whereas in males, it contained 279 bacterial OTUs and one archaeal OTU. In females, Bacteroidetes and Spirochaetes were significantly more abundant than in male camels, whereas Lentisphaerae and Euryarchaeota were significantly abundant in males. According to Principal Coordinate Analysis and UPGMA clustering, grouping with respect to sex was observed. The functional prediction results showed differences such as energy production and conversion, and that the cell wall/membrane/envelope were enriched in female camels. The fecal microbiome of male camels was rich in amino acid, lipid transport and metabolism.

Molecular characterisation of Echinococcus granulosus sensu lato genotypes in dromedary camels from extreme Sahara of Algeria based on analysis of nad2 and nad5 genetic markers

Cystic echinococcosis is parasitic disease caused by the metacestodes belonging to the Echinococcus granulosus sensu lato (s.l.) species complex. Cystic echinococcosis is of considerable economic and public health importance. It is endemic in both livestock and humans in North African countries, including Algeria. The present study aimed to characterize E. granulosus s.l. genotypes in dromedary camels (Camelus dromedarius) from the extreme Sahara of Algeria, using recently developed mitochondrial genetic markers (NADH dehydrogenase subunit 2 and NADH dehydrogenase subunit 5) for reliable identification of different genotypes. A total of 75 Echinococcus cysts were collected from 49 dromedary camels, including 65 and 10 cysts from 45 and four camels originating from two slaughterhouses of Tindouf and Illizi provinces, respectively. E. granulosus sensu stricto (s.s.) G1 and G3 were identified in camels from both areas based on nad5 (649 bp) gene sequences, whereas E. granulosus s.l. G6 was identified in camels from Tindouf region based on concatenated nad5 and nad2 gene sequences (total 1336 bp). Identified samples clustered into 11 different haplotypes (ALG1-ALG11) including four haplotypes (ALG8-ALG11) for E. granulosus s.s. G1, one haplotype (ALG7) for E. granulosus s.s. G3, and six haplotypes (ALG1-ALG6) for E. granulosus s.l. G6. The present study provides valuable molecular data including genotyping and haplotypic variability on E. granulosus s.l. in dromedary camels from two regions in the extreme Sahara of Algeria. Future characterization of the G1, G3 and G6 samples based on sequencing of complete mitochondrial genomes would be of considerable significance for a more comprehensive understanding of molecular epidemiology of CE in Algeria.

Betaretrovirus infections in dromedary camels in Saudi Arabia

Background

Retroviral infections have been reported in many species of animals, especially cattle, sheep and goats. However, there are no available reports about retrovirus infection in dromedary camels. Several dromedary camels showed visible tumor‐like lesions on and around the nostrils as well as around the eyes.

Objectives

Following are the objectives: to identify the causative agents of these identified tumours in dromedary camels and to perform molecular characterization of the detected strains of the causative agent.

Methods

We extracted the nucleic acids from some fresh lesions out of these animals, and then amplified some key retrovirus genes. We amplified several regions of the rotavirus genome using the PCR technique. The obtained sequences were assembled and the phylogenetic trees were conducted per each target retrovirus gene.

Results

Our results revealed a high degree of identity to some retroviruses of sheep. Phylogenetic analysis based on some retrovirus genes revealed that the causative agents of these lesions are closely related to sheep retroviruses, particularly the Jaagsiekte sheep Retrovirus (JSRV) and the ENTV.

Conclusions

To the best of our knowledge, this is the first report of retrovirus infections in dromedary camels in the Arabian Peninsula. This highlights the possible species jump for the retrovirus from sheep and goats to the dromedary camels, which live in close proximity with these animals in many parts of the world, especially the Arabian Peninsula.

Our findings show for the first time the detection, identification and molecular characterization of retrovirus infection in dromedary camels in Saudi Arabia. We detected betaretrovirus infections in skin lesions in the head and around the nostrils and eyes of some dromedary camels. Our findings clearly demonstrate the causative agent for these lesions belongs to the betaretrovirus. The reported sequences out of these lesions showed a high degree of similarity to some sheep retroviruses, especially the Jaagsiekte sheep Retrovirus (JSRV). This study suggests that the potential interspecies transmission of retroviruses from sheep to dromedary camels live in close proximity of each other.

Factors affecting outcomes of embryo transfer in dromedary camels: a retrospective study

The present study aimed to use a comprehensive approach for evaluating 12 factors related to embryo quality (shape, size and transparency), donors (age, ET type, number of recovered embryos and day of uterine flushing), recipients (age), males (age and individual variations), and environment (season and year) which could affect the outcome of ET in terms of pregnancy (PR) and pregnancy losses in dromedary camels. During three breeding seasons, 116 donors females were mated repeatedly at 12 to 14-day intervals by fertile camel males (n=33) without stimulation of the ovaries (WSPO). Superovulation (SPO ET) regimen was applied for each donor female twice or thrice per season. In the occasions of applying superovulation regimen, donor females having an ovulatory follicle were mated instead of GnRH administration and superovulation regimen was applied 4 days post-mating (MIX ET). The uteri of all donor females were flushed at Day 8 or 9 post-mating and a total of 2095 embryos were recovered and transferred individually to 924 recipient females. Pregnancy diagnoses were conducted at Day 10 after ET (Days 18 to 19 of gestation) by using progesterone assay and by transrectal ultrasonography (TRU) at Days 30 and 60 of gestation. By using logistic regression analysis, transparency of embryos and age of recipient females had significant effects on PR at Days 18 to 19 (P< 0.01), 30 (P < 0.01) and 60 (P < 0.01; P < 0.05, respectively) of gestation. The shape of embryos had significant effects on the PR at Days 30 (P < 0.05) and 60 (P < 0.01) of gestation. Type of ET and the breeding season (year) had significant (P< 0.05) effects on the PR at Day 30, while day of flushing had the same effect on PR at Day 60. Regarding the pregnancy losses, transparency and shape of the embryo, type of ET, breeding season had significant (P<0.05) effect on the late embryonic mortalities (LEM) and shape and season of year had significant (P<0.01 and P< 0.05, respectively) effect on LEM/early fetal mortalities (EFM). Regarding male individual factor, there was a tendency for a significant (P =0.055) effect of camel males on the PR at Days 18 to 19 and rate of LEM. In conclusion, transferring a spherical, transparent or a large-sized embryo (> 750 µm) into recipient females aging between 8 and 11 y could greatly improve the PR from Days 18 to 60 of gestation. Also, embryo recovered from donor females with Mix ET type or embryos sired by certain camel male or at Day 8 post mating of the donor could improve the two-month PR. In addition, transferring a transparent or spherical-shaped embryo or embryos recovered from donor females with SPO or Mix ET could reduce the pregnancy losses during the first two months of pregnancy.

Scanning electron microscopy and morphometric analysis of superficial corneal epithelial cells in dromedary camel (Camelus dromedarius)

It is likely that superficial corneal epithelial cells (SCECs) of the dromedary camels have a significant role in their survival at arid and semiarid regions. To the best of our knowledge, SCECs of camels' eyes have not been characterized previously using scanning electron microscopy (SEM), combined with morphometric analysis. Therefore, in the current study, we aim to describe the shape, topographical distribution, and density of SCECs associated with morphometric analysis using SEM. Twelve healthy adult camels' corneas were obtained immediately after slaughter. Each cornea has been divided into nine parts: central (C), middle dorsal (MD), middle ventral (MV), middle nasal (MN), middle temporal (MT), peripheral dorsal (PD), peripheral ventral (PV), peripheral nasal (PN), and peripheral temporal (PT). SCECs were distinguished and characterized into light, medium, and dark mosaics. The polygonal cells have been externally covered with microplicae that were more numerous above the light cells. The topographic distribution of light, medium, and dark cells revealed a well-defined concentration of light cells in excess of other cells in all parts as follows: PV (92.5%), PN (78.5%), MN (78%), MT (74.7%), PD (73.8%), PT (70.7%), MV (68.7%), MD (66.3%), and C (19.3%). The PV part recorded the highest density of light cells, while the C portion showed the lowest density for the same cells. We concluded that the light cells extensively predominate in all parts of the camels' cornea except the C part, indicating an adaptive modification to the harsh environment. Additionally, the PV and PN parts represent the permanent and endogenous source as well as a proliferative reserve for SCECs in dromedary camel.

Identification of Hepatitis E Virus Genotypes 3 and 7 in Israel: A Public Health Concern?

Background: Hepatitis E (HEV) is an emerging cause of viral hepatitis worldwide. Swine carrying hepatitis E genotype 3 (HEV-3) are responsible for the majority of chronic viral hepatitis cases in developed countries. Recently, genotype 7 (HEV-7), isolated from a dromedary camel in the United Arab Emirates, was also associated with chronic viral hepatitis in a transplant recipient. In Israel, chronic HEV infection has not yet been reported, although HEV seroprevalence in humans is ~10%. Camels and swine are >65% seropositive. Here we report on the isolation and characterization of HEV from local camels and swine. Methods: Sera from camels (n = 142), feces from swine (n = 18) and blood from patients suspected of hepatitis E (n = 101) were collected during 2017–2020 and used to detect and characterize HEV sequences. Results: HEV-3 isolated from local swine and the camel-derived HEV-7 sequence were highly similar to HEV-3f and HEV-7 sequences (88.2% and 86.4%, respectively) related to viral hepatitis. The deduced amino acid sequences of both isolates were also highly conserved (>98%). Two patients were HEV-RNA positive; acute HEV-1 infection could be confirmed in one of them. Discussion: The absence of any reported HEV-3 and HEV-7 infection in humans remains puzzling, especially considering the reported seroprevalence rates, the similarity between HEV sequences related to chronic hepatitis and the HEV genotypes identified in swine and camels in Israel.

Aspects of Molecular Genetics in Dromedary Camel

Dromedary camels are unique in their morphological and physiological characteristics and are capable of providing milk and meat even under extreme environmental conditions. Like other species, the dromedary camel has also benefitted from the development of the molecular genetics to increase the knowledge about different aspect in camel genetics (genetic variation, molecular marker, parentage control, gene of interest, whole genome, dating…etc.). In this paper we review the different molecular genetic technics used in this particular species and future prospects. Dromedary genetic studies started in the end of the 1980s with phenotypic evaluation and the attempts to highlight the protein and biochemical diversity. In the 2000s, with the development of molecular markers such as microsatellites, genetic diversity of different types in several countries were estimated and microsatellites were also used for parentage control. In terms of genetic characterization, microsatellites revealed a defined global structure, differentiating East African and South Arabian dromedaries from North African, North Arabian, and South Asian individuals, respectively. Also, mitochondrialDNA sequence analysis of ancient DNA proved to be crucial in resolving domestication processes in dromedaries. Ancient and modern DNA revealed dynamics of domestication and cross-continental dispersion of the dromedary. Nuclear SNPs, single nucleotide polymorphisms changes that occur approximately each 1000 bps in the mammalian genome were also applied in some studies in dromedary. These markers are a very useful alternative to microsatellites and have been employed in some studies on genetic diversity and relevant phenotypic traits in livestock. Finally, thanks to the use of Next Generation Sequencing (NGS) the whole-genome assemblies of the dromedary (Camelus dromedarius) and a work to establish the organization of the dromedary genome at chromosome level were recently published.

The Youngest, the Heaviest and/or the Darkest? Selection Potentialities and Determinants of Leadership in Canarian Dromedary Camels

Simple Summary

Genetic selection of camels for behavioral traits is not an extended practice in livestock scenarios. Given the existence of pleiotropic genes that influence two or more seemingly unrelated phenotypic traits, here we studied the sociodemographic, zoometric and phaneroptical characteristics potentially determining the intraherd leadership role in Canarian camels. This local endangered breed is mainly reared in same-sex groups because of biased morphostructural preferences, that is, tourism/leisure and milk production for males and females, respectively. The attribute most influencing leadership role was sexual status, as gelded animals more frequently initiated group movements. Furthermore, younger camels were mainly endorsed as group leaders, a condition that could be ascribed to their recognized fluid intelligence and need for constant social and environmental interaction. Referring to zoometrics and phaneroptics, the heaviest and darkest-coated dromedaries were significantly more prone to reaching higher positions in the leadership hierarchy. The presence of white-haired zones in the extremities, head and neck as well as iris depigmentation had non-negligible influence on this type of social organization. This information is valuable for application both in refining animal handling procedures and in genetic selection of animals for their social behavior.

Abstract

Several idiosyncratic and genetically correlated traits are known to extensively influence leadership in both domestic and wild species. For minor livestock such as camels, however, this type of behavior remains loosely defined and approached only for sex-mixed herds. The interest in knowing those animal-dependent variables that make an individual more likely to emerge as a leader in a single-sex camel herd has its basis in the sex-separated breeding of Canarian dromedary camels for utilitarian purposes. By means of an ordinal logistic regression, it was found that younger, gelded animals may perform better when eliciting the joining of mates, assuming that they were castrated just before reaching sexual maturity and once they were initiated in the pertinent domestication protocol for their lifetime functionality. The higher the body weight, the significantly (p < 0.05) higher the score in the hierarchical rank when leading group movements, although this relationship appeared to be inverse for the other considered zoometric indexes. Camels with darker and substantially depigmented coats were also significantly (p < 0.05) found to be the main initiators. Routine intraherd management and leisure tourism will be thus improved in efficiency and security through the identification and selection of the best leader camels.

Outbreak of a Systemic Form of Camelpox in a Dromedary Herd (Camelus dromedarius) in the United Arab Emirates

Camelpox virus (CMLV) is the causative agent of camelpox, which frequently occurs in the Old World camelids-rearing countries except for Australia. It has also been described in experimentally inoculated New World camelids. Camelpox outbreaks are often experienced shortly after the rainy season, which occurs twice a year on the Arabian Peninsula because of the increased density of the insect population, particularly mosquitos. A systemic form of camelpox outbreak in seven dromedary camels was diagnosed by histology, virus isolation, and PCR. A phylogenetic analysis using full length CMLV genomes of the isolated CMLV strains showed a single phylogenetic unit without any distinctive differences between them. The United Arab Emirates (UAE) isolate sequences showed phylogenetical relatedness with CMLV isolates from Israel with only minor sequence differences. Although the sequences of viruses from both countries were closely related, the disease manifestation was vastly different. Our study shows that the virulence is not only determined by genetic features of CMLV alone but may also depend on other factors such as unknown aspects of the host (e.g., age, overall fitness), management, and the environment.

Bacterial phagocytosis and reactive oxygen species production by camel neutrophils and monocytes are influenced by the type of anticoagulation agent

Background and Aim

Anticoagulants with different modes of action are used in the collection of camel blood samples. In the innate immune response, camel neutrophils and monocytes can play several roles during infection and inflammation. For anticoagulants ethylenediaminetetraacetic acid (EDTA) and heparin, research has described their effects on different parameters of the immune system. However, to date, no research has examined the effects of anticoagulants on the functional activity of camel phagocytes. Therefore, this study analyzed the influence of K₃EDTA and lithium heparin on the antimicrobial activity of camel neutrophils and monocytes.

Materials and Methods

Camel leukocytes were separated from blood collected in EDTA or heparin tubes, and their phagocytosis and reactive oxygen species (ROS) production activity were analyzed by flow cytometry after stimulation with Staphylococcus aureus or Escherichia coli bacteria.

Results

In comparison to the cells collected from the EDTA blood, the camel neutrophils and monocytes separated from the heparin blood showed higher phagocytosis activity of S. aureus and E. coli. In addition, the neutrophils and monocytes produced significantly more ROS when the blood was collected in the heparin tubes.

Conclusion

The antimicrobial functions of camel neutrophils and monocytes are significantly affected by the type of anticoagulation agent. Therefore, using heparin rather than EDTA as an anticoagulant is recommended when performing the functional analysis of phagocytosis and ROS production of camel phagocytes.

Genetic parameters of gestation length trait in dromedary camels (Camelus dromedarius)

Gestation length (GL) data of dromedary camels were analysed for the period from 2007 to 2018. The database of the largest dairy camel herds (Dubai, United Arab Emirates) was used in this study. The data of 4,084 camels included in the assessment were classified into six ecotypes (Emirati, Emirati cross, Black, Pakistani, Saudi-Sudanese and Saudi cross). The aim of the study was to describe the heritability of GL of camels and the breeding value (BV) of sires for this trait. The genetic parameters of GL were estimated by the General Linear Model method and two Best Linear Unbiased Prediction (BLUP) animal models as well. The mean (±SE) of GL of camels was 384.3 ± 0.2 days. The direct heritability of GL (0.26 ± 0.06-0.36 ± 0.08) was higher than the maternal heritability (0.00 ± 0.05-0.13 ± 0.06) obtained. The maternal permanent environmental effect (0.15 ± 0.05) was similar to the results estimated previously in dromedary camel, but higher than the data reported by relevant sources in other species. Based on the results of this study it can be concluded that the GL of dromedary camels is a species-specific value similar to that in cattle, which is less affected by the maternal influence. Considerable differences (16 days) exist among male dromedaries in their BV for the GL trait.

Co-localization of nociceptive markers in the lumbar dorsal root ganglion and spinal cord of dromedary camel

Nociceptive markers in mice have been identified in two distinct peptidergic and nonpeptidergic neurons in the dorsal root ganglion (DRG) and distributed in different laminae of the dorsal horn of the spinal cord. Recently, however, a study in humans showed a significant overlapping in these two populations. In this study, we investigated the distribution of various nociceptive markers in the lumbar DRG and spinal cord of the dromedary camel. Immunohistochemical data showed a remarkable percentage of total neurons in the DRG expressed IB4 binding (54.5%), calcitonin gene-related peptide (CGRP; 49.5%), transient receptor potential vanilloid 1 (TRPV1; 48.2%), and nitric oxide synthase (NOS; 30.6%). The co-localization data showed that 89.6% and 74.0% of CGRP- and TRPV1-labeled neurons, respectively, were IB4 positive. In addition, 61.6% and 84.2% of TRPV1- and NOS-immunoreactive neurons, respectively, were also co-localized with CGRP. The distribution of IB4, CGRP, TRPV1, substance P, and NOS immunoreactivities in the spinal cord were observed in lamina I and outer lamina II (IIo). Quantitative data showed that 82.4% of IB4-positive nerve terminals in laminae I and IIo were co-localized with CGRP, and 86.0% of CGRP-labeled terminals were co-localized with IB4. Similarly, 85.1% of NOS-labeled nerve terminals were co-localized with CGRP. No neuropeptide Y (NPY) or cholecystokinin (CCK) immunoreactivities were detected in the DRG, and no co-localization between IB4, NPY, and CCK were observed in the spinal cord. Our results demonstrate marked convergence of nociceptive markers in the primary afferent neurons in camels, which is similar to humans rather than the mouse. The data also emphasizes the importance of interspecies differences when selecting ideal animal models for studying nociception and treating chronic pain.

Immunomodulatory Effects of the Cyclooxygenase Inhibitor Lornoxicam on Phenotype and Function of Camel Blood Leukocytes

Simple Summary

The present study investigated the immunomodulatory effects of the unspecific cyclooxygenase inhibitor lornoxicam on the immunophenotype and some functions of dromedary camel blood leukocytes. Intravenous injection of camels with a single dose of lornoxicam induced a significant change in the camel leukogram, which is characterized by reduced cell numbers of all leukocyte subpopulations. In vitro analysis of cell vitality revealed a pro-apoptotic effect of lornoxicam on camel leukocytes, which may be responsible for the lornoxicam-induced leukocytopenia in vivo. Functional ex vivo and in vitro analysis of the key antimicrobial functions, phagocytosis and ROS production indicates inhibitory effects of lornoxicam on the antimicrobial capacity of the blood phagocytes, monocytes and neutrophils. Furthermore, lornoxicam induced an anti-inflammatory phenotype of monocytes, characterized by reduced expression of major histocompatibility complex (MHC) class II molecules and increased expression of CD163 molecules. The present study identified for the first time inhibitory effects of the COX-inhibitor lornoxicam on some phenotypic and functional properties of camel blood immune cells and recommends considering these effects when using lornoxicam in camel medicine.

Abstract

(1) Background: Lornoxicam is a nonsteroidal anti-inflammatory drug (NSAID) with analgesic, antiphlogistic and antipyretic effects. The improved tolerance of lornoxicam due to the relatively shorter elimination half-life in comparison to other members of the oxicams may favor its application in the management of pain and inflammation in race dromedary camels. There are no studies conducted yet on the immunomodulatory or immunotoxilogic effect of lornoxicam in camels. Therefore, the current study aimed to evaluate the immunomodulatory effects of the cyclooxygenase inhibitor lornoxicam on some phenotypic and functional properties of camel blood leukocytes; (2) Methods: Using flow cytometry, blood leukocyte composition, monocyte phenotype, and antimicrobial functions of neutrophils and monocytes were analyzed ex vivo after a single dose injection with lornoxicam. In addition, the effect of in vitro incubation of camel blood with lornoxicam on leukocyte cell vitality and antimicrobial functions were evaluated; (3) Results: The injection of camels with a single dose of lornoxicam resulted in a significant change in their leukogram with reduced numbers of total leukocytes, neutrophils, eosinophils, monocytes, and lymphocytes. Within the lymphocyte population, the numbers of CD4⁺ T cells, γδ T cells, and B cells decreased significantly in blood after injection of camels with lornoxicam. In addition, injection of lornoxicam resulted in decreased abundance of major histocompatibility complex (MHC) class II molecules and increased abundance of the scavenger receptor CD163 on blood monocytes, indicating an anti-inflammatory phenotype of monocytes. Functionally, administration of lornoxicam decreased the capacity of camel neutrophils and monocytes to uptake bacteria and to produce reactive oxygen species (ROS) after bacterial stimulation. Similarly, the in vitro whole blood incubation with lornoxicam resulted in reduced phagocytosis and ROS production activity of the camel blood phagocytes. Flow cytometric analysis of cell vitality, including cell necrosis and apoptosis, revealed a pro-apoptotic effect of lornoxicam on camel leukocytes; (4) Conclusions: Lornoxicam administration, at the dose and intervals utilized herein, induces significant changes in the phenotype and function of camel blood leukocytes. The reduced cell numbers of all studied leukocyte subpopulations in lornoxicam-treated camels, which seems to be a result of enhanced cell apoptosis, indicates an inhibitory effect rather than a modulatory effect of lornoxicam on the camel immune system, which need to be considered when using lornoxicam in camel medicine.

Scanning Electron Microscopic Findings on Respiratory Organs of Some Naturally Infected Dromedary Camels with the Lineage-B of the Middle East Respiratory Syndrome Coronavirus (MERS-CoV) in Saudi Arabia-2018

The currently known animal reservoir for MERS-CoV is the dromedary camel. The clinical pattern of the MERS-CoV field infection in dromedary camels is not yet fully studied well. Some pathological changes and the detection of the MERS-CoV antigens by immunohistochemistry have been recently reported. However, the nature of these changes by the scanning electron microscope (SEM) was not revealed. The objective of this study was to document some changes in the respiratory organs induced by the natural MERS-CoV infection using the SEM. We previously identified three positive animals naturally infected with MERS-CoV and two other negative animals. Previous pathological studies on the positive animals showed varying degrees of alterations. MERS-CoV-S and MERS-CoV-Nc proteins were detected in the organs of positive animals. In the current study, we used the same tissues and sections for the SEM examination. We established a histopathology lesion scoring system by the SEM for the nasal turbinate and trachea. Our results showed various degrees of involvement per animal. The main observed characteristic findings are massive ciliary loss, ciliary disorientation, and goblet cell hyperplasia, especially in the respiratory organs, particularly the nasal turbinate and trachea in some animals. The lungs of some affected animals showed signs of marked interstitial pneumonia with damage to the alveolar walls. The partial MERS-CoV-S gene sequencing from the nasal swabs of some dromedary camels admitted to this slaughterhouse confirms the circulating strains belong to clade-B of MERS-CoV. These results confirm the respiratory tropism of the virus and the detection of the virus in the nasal cavity. Further studies are needed to explore the pathological alterations induced by MERS-CoV infection in various body organs of the MERS-CoV naturally infected dromedary camels.

Retrograde flushing collection and freezing of dromedary camel epididymal spermatozoa with seminal plasma

The objectives of this study were to describe the parameters of dromedary camel epididymal spermatozoa collected by retrograde flushing (RF) technique and to evaluate the freezability of the collected sperm, diluted with and without the supplementation of seminal plasma (SP). Two experiments were conducted: in Experiment 1, ES were recovered within 6-8 h after castration; selected samples were diluted with a Tris-citrate egg-yolk glycerolated buffer and frozen. In Experiment 2, epididymides were stored for 24 h at 4 °C before RF and semen samples were frozen after dilution with a Tris-lactose egg-yolk glycerolated extender with and without 15% SP. In Experiment 1, eight semen samples were obtained from ten epididymides with a mean of 500 × 106 total spermatozoa recovered, per flushed epididymis. Mean post-thaw motility and progressive motility were 75 and 17%, respectively. In Experiment 2, 15 samples were collected, out of the 18 epididymides (mean number of collected spermatozoa: 700 × 106), and 13 of these samples were of excellent quality. Post-thaw parameters were not satisfactory but the supplementation of the freezing medium with 15% SP improved the progressive motility and kinematic parameters of the spermatozoa.

Zoonotic implications of camel diseases in Iran

Approximately 60% of all human pathogens and 75% of emerging infectious diseases are zoonotic (of animal origin). Camel zoonotic diseases can be encountered in all camel-rearing countries. In this article, all studies carried out on camel zoonotic diseases in Iran are reviewed to show the importance of camels for public health in this country. More than 900 published documents were systematically searched to find relevant studies from 1,890 until late 2018. The collected articles were classified according to the aetiological agents. In this study, 19 important zoonotic diseases were reported among Iranian camels including listeriosis, leptospirosis, plague, Q fever, brucellosis, campylobacteriosis, tuberculosis, pasteurellosis, clostridiosis, salmonellosis, Escherichia coli infections, rabies, camelpox, Middle East respiratory syndrome coronavirus, Crimean-Congo haemorrhagic fever, echinococcosis, cryptosporidiosis, toxoplasmosis and dermatophytosis, most of which belong to bacterial, viral, parasitic and fungal pathogens, respectively. Results show that camels are one of the most important sources of infections and diseases in human; therefore, continuous monitoring and inspection programs are necessary to prevent the outbreak of zoonotic diseases caused by this animal in humans.

Isolation, identification and associated risk factors of non-tuberculous mycobacteria infection in humans and dromedary camels in Samburu County, Kenya

Non-tuberculous mycobacteria are of public health significance, and zoonotic infection is attributed to the sociocultural practice of consumption of raw milk and the close human-livestock contact in pastoral communities. This study aimed at isolation, identification of mycobacteria from human sputum and camel milk and risk factors assessment in Samburu East, Kenya. Six hundred and twelve camels and 48 people presumed to have tuberculosis (TB) from 86 households in Wamba and Waso regions were screened. Camels were categorized into Somali, Turkana and Rendile breeds. Single intradermal comparative tuberculin test (SICTT) was used as a herd-screening test on lactating camels and a milk sample collected from reactive camels. Sputum samples were collected from eligible members of participating households. A standard questionnaire on possible risk factors for both humans and camels was administered to respective household heads or their representatives. Total camel skin test reactors were 238/612 (38.9%). Milk and sputum samples were analysed at KEMRI/TB research laboratory for microscopy, GeneXpert^® , culture and identification. Isolates were identified using 16S rRNA gene sequencing at Inqaba biotec in South Africa. Sixty-four isolates were acid-fast bacilli (AFB) positive of which M. fortuitum (3), M. szulgai (20), M. monacense (5), M. lehmanni (4), M. litorale (4), M. elephantis (3), M. duvalii (3), M. brasiliensis (1), M. arcueilense (1) and M. lentiflavum (1) were from milk; M. fortuitum (1), M. szulgai (2) and M. litorale (1) were from humans. Risk factors included the following: Turkana breed (OR = 3.4; 95% CI: 1.2-9.3), replacements from outside the County (OR = 2.1; 95% CI: 0.3-12.3), presence of other domestic species (small stock; OR = 4.6) and replacement from within the herd (OR = 3.2; 95% CI: 0.7-14.7). Zoonotic risk practices included raw milk consumption, shared housing and handling camels. Monitoring of zoonotic NTM through surveillance and notification systems is required.

Genomic Sequencing and Analysis of Eight Camel-Derived Middle East Respiratory Syndrome Coronavirus (MERS-CoV) Isolates in Saudi Arabia

Middle East respiratory syndrome coronavirus (MERS-CoV) causes severe respiratory illness in humans; the second-largest and most deadly outbreak to date occurred in Saudi Arabia. The dromedary camel is considered a possible host of the virus and also to act as a reservoir, transmitting the virus to humans. Here, we studied evolutionary relationships for 31 complete genomes of betacoronaviruses, including eight newly sequenced MERS-CoV genomes isolated from dromedary camels in Saudi Arabia. Through bioinformatics tools, we also used available sequences and 3D structure of MERS-CoV spike glycoprotein to predict MERS-CoV epitopes and assess antibody binding affinity. Phylogenetic analysis showed the eight new sequences have close relationships with existing strains detected in camels and humans in Arabian Gulf countries. The 2019-nCov strain appears to have higher homology to both bat coronavirus and SARS-CoV than to MERS-CoV strains. The spike protein tree exhibited clustering of MERS-CoV sequences similar to the complete genome tree, except for one sequence from Qatar (KF961222). B cell epitope analysis determined that the MERS-CoV spike protein has 24 total discontinuous regions from which just six epitopes were selected with score values of >80%. Our results suggest that the virus circulates by way of camels crossing the borders of Arabian Gulf countries. This study contributes to finding more effective vaccines in order to provide long-term protection against MERS-CoV and identifying neutralizing antibodies.

Camelids and Cattle Are Dead-End Hosts for Peste-des-Petits-Ruminants Virus

Peste-des-petits-ruminants virus (PPRV) causes a severe respiratory disease in small ruminants. The possible impact of different atypical host species in the spread and planed worldwide eradication of PPRV remains to be clarified. Recent transmission trials with the virulent PPRV lineage IV (LIV)-strain Kurdistan/2011 revealed that pigs and wild boar are possible sources of PPRV-infection. We therefore investigated the role of cattle, llamas, alpacas, and dromedary camels in transmission trials using the Kurdistan/2011 strain for intranasal infection and integrated a literature review for a proper evaluation of their host traits and role in PPRV-transmission. Cattle and camelids developed no clinical signs, no viremia, shed no or only low PPRV-RNA loads in swab samples and did not transmit any PPRV to the contact animals. The distribution of PPRV-RNA or antigen in lymphoid organs was similar in cattle and camelids although generally lower compared to suids and small ruminants. In the typical small ruminant hosts, the tissue tropism, pathogenesis and disease expression after PPRV-infection is associated with infection of immune and epithelial cells via SLAM and nectin-4 receptors, respectively. We therefore suggest a different pathogenesis in cattle and camelids and both as dead-end hosts for PPRV.

Bactrian camels shed large quantities of Middle East respiratory syndrome coronavirus (MERS-CoV) after experimental infection. Emerg Microbes Infect 2019;8:717-723. [PMID: 31119984 PMCID: PMC6534258 DOI: 10.1080/22221751.2019.1618687]

In 2012, Middle East respiratory syndrome coronavirus (MERS-CoV) emerged. To date, more than 2300 cases have been reported, with an approximate case fatality rate of 35%. Epidemiological investigations identified dromedary camels as the source of MERS-CoV zoonotic transmission and evidence of MERS-CoV circulation has been observed throughout the original range of distribution. Other new-world camelids, alpacas and llamas, are also susceptible to MERS-CoV infection. Currently, it is unknown whether Bactrian camels are susceptible to infection. The distribution of Bactrian camels overlaps partly with that of the dromedary camel in west and central Asia. The receptor for MERS-CoV, DPP4, of the Bactrian camel was 98.3% identical to the dromedary camel DPP4, and 100% identical for the 14 residues which interact with the MERS-CoV spike receptor. Upon intranasal inoculation with 107 plaque-forming units of MERS-CoV, animals developed a transient, primarily upper respiratory tract infection. Clinical signs of the MERS-CoV infection were benign, but shedding of large quantities of MERS-CoV from the URT was observed. These data are similar to infections reported with dromedary camel infections and indicate that Bactrians are susceptible to MERS-CoV and given their overlapping range are at risk of introduction and establishment of MERS-CoV within the Bactrian camel populations.

Diversity and prevalence of parasitic infestation with zoonotic potential in dromedary camel ( ) and fat-tailed sheep (dhumba) in Bangladesh

OBJECTIVE

Parasitic infestation is a major cause of losses in livestock production in tropical regions. A cross-sectional study was conducted to determine the prevalence of Gastro-intestinal (GI) parasites of dromedary camel (Camelus dromedarius) and fat-tailed sheep (dhumba), and the prevalence of hemoparasites in camel from Dhaka, Bangladesh.

MATERIALS AND METHODS

A total of 87 fecal samples (32 dhumba and 55 camel) and 55 camel blood samples were collected during September-October 2015. Fecal samples were examined by direct smear, sedimentation method, flotation technique, and McMaster technique for GI parasite. Giemsa stained blood smears were examined under microscope for hemoparasite detection.

RESULTS

62% camel (n = 34; 95% confidence interval (CI): 47.7-74.6) were infected with at least one genus of parasite. 15% camel were harboring more than one genus of parasite. The prevalence of GI parasite and hemoparasite in camel were recorded as Trichuris spp. (n = 16; 29%; 95% CI: 17.6-42.9), Balantidium coli (n = 12; 22%; 95% CI: 11.8-35.0), Trichostrongylus spp. (n = 7; 13%; 95% CI: 5.3-24.5), Strongyloides spp. (n = 5; 9%; 95% CI: 3.0-20.0), Anaplasma spp. (n = 5; 9%; 95% CI: 3.02-20.0), Paragonimus spp. (n = 1; 2%; 95% CI: 0.05-9.7), Schistosoma spp. (n = 1; 2%; 95% CI: 0.05-9.7), Hymenolepis spp. (n = 1; 2%; 95% CI: 0.05-9.7), Moniezia spp. (n = 1; 2%; 95% CI: 0.05-9.7), and Babesia spp. (n = 1; 2%; 95% CI: 0.05-9.7). Mean EPG feces of camel was 291.76 ± 42.03 with a range of 0-1,400. Total 59.4% dhumba (n = 19; 95% CI: 41-76) were positive for GI parasite, including Trichostrongylus spp. (n = 10; 31.3%; 95% CI: 16.1-50), Strongyloides spp. (n = 9; 28%; 95% CI: 13.8-46.8), B. coli (n = 5; 15.6%; 95% CI: 5.3-32.8), and Trichuris spp. (n = 4; 12.5%; 95% CI: 3.5-28.9).

CONCLUSIONS

High percentage of parasitic infestation in camel and dhumba in the present study refers to the necessity of use of anthelmintic for health and production improvement and to prevent zoonotic parasite transmission to animal handler and workers.

A Near Chromosome Assembly of the Dromedary Camel Genome

The dromedary camel is an economically and socially important species of livestock in many parts of the world, being used for transport and the production of milk and meat. Much like cattle and horses, the camel may be found in industrial farming conditions as well as used in sporting. Camel racing is a multi-million dollar industry, with some specimens being valued at upward of 9.5 million USD. Despite its apparent value to humans, the dromedary camel is a neglected species in genomics. While cattle and other domesticated species have had much attention in terms of genome assembly, the camel has only been assembled to scaffold level, which does not give a clear indication of the order or chromosomal location of sequenced fragments. In this study, the Reference Assistant Chromosome Assembly (RACA) algorithm was implemented to use read-pair information of camel scaffolds, aligned with the cattle and human genomes in order to organize and orient these scaffolds in a near-chromosome level assembly. This method generated 72 large size fragments (N50 54.36 Mb). These predicted chromosome fragments (PCFs) were then compared with comparative maps of camel and cytogenetic map of alpaca chromosomes, allowing us to further upgrade the assembly. This dromedary camel assembly will be an invaluable tool to verify future camel assemblies generated with chromatin conformation or/and long read technologies. This study provides the first near-chromosome assembly of the dromedary camel, thus adding this economically important species to a growing pool of knowledge regarding the genome structure of domesticated livestock.

Disseminated tuberculosis in a cow and a dromedary bull-camel in Zamfara State in Nigeria

In 2017, cases of generalized tuberculosis (TB) were identified in a cow and a bull-camel, slaughtered at the Gusau abattoir in Zamfara State Nigeria. The objective of this study was to identify the cause of the gross pathology on the account of disseminated lesions widely distributed in different body parts of the animals. Tissue samples were analysed using Ziehl-Neelsen (ZN) stain and region of difference (RD) deletion typing. Results obtained by laboratory investigations revealed infection with acid-fast tubercle bacilli in affected tissues from the cow and the dromedary bull-camel. This study presents the first molecular evidence of Mycobacterium bovis infection in a Nigerian dromedary camel, demonstrated the ease of identification of the acid-fast bacilli using molecular method which improves diagnosis and can aid epidemiological studies.

Temperature dependency of whole blood viscosity and red cell properties in desert ungulates: Studies on scimitar-horned oryx and dromedary camel

Background

The dromedary camel and the oryx antelope are exposed to excessive heat and solar radiation in their desert habitat. Desertification of areas with by now little rainfall may occur eventually. Well-adapted large animal species show us what is needed to survive in scorching regions.

Methods

Four scimitar-horned oryx antelopes (Oryx dammah), 10 camels (Camelus dromedarius), nine South African Merino sheep, and 17 Nguni cows were tested for RBC aggregation, RBC elongation, and plasma viscosity. The temperature dependency of blood viscosity was tested in 10 camels and compared to human reference values.

Results

Unlike sheep, Nguni cow, and dromedary camel, oryx RBCs aggregate in native plasma (M0:5.2 (3.3/6.7); M1:18.1 (16.7/27.9); Myrenne MA1). Elongation indices of oryx RBCs were intermediate to low (EImax: 22.6 (19.2/25.3); SS1/2 3.67 (2.52/4.95); Rheodyn SSD). Camel RBCs did not display the typical SS/EI curve by rotational ektacytometry. In-vitro blood viscosity (Physica MCR302) was lower in camels than in human blood at equal hematocrit. A decrease of temperature had only little effect on camel blood. At 10 s−1, blood viscosity in camel increased from 2.18mPa*s (2.01/2.37) at 42◦C to 4.39mPa*s (4.22/4.51) at 12◦C. In human blood, viscosity ranged from 8.21mPa*s (6.95/8.25) at 37◦C to 15.52mPa*s (14.25/16.03) at 12◦C. At 1000 s−1, blood viscosity in camel ranged from 2.00mPa*s (1.95/2.04) at 42◦C to 3.98mPa*s (3.88/4.08) at 12◦C. In human blood, viscosity ranged from 5.35mPa*s (4.96/5.87) at 37◦C to 11.24mPa*s (10.06/11.17) at 12◦C.

Conclusions

Desert ungulates may need RBC membranes, which are fortified to withstand changes in osmolality during dehydration-rehydration cycles. This reduces RBC deformability. Dromedary camel blood does not undergo stark changes in viscosity with changes in temperature. Therefore, blood fluidity could be rather maintained during the day and night cycle. This should reduce the need of the vascularity to rhythmically adapt to changing shear forces when camels experience heterothermy.

Zoonotic origin and transmission of Middle East respiratory syndrome coronavirus in the UAE

Since the emergence of Middle East respiratory syndrome coronavirus (MERS-CoV) in 2012, there have been a number of clusters of human-to-human transmission. These cases of human-to-human transmission involve close contact and have occurred primarily in healthcare settings, and they are suspected to result from repeated zoonotic introductions. In this study, we sequenced whole MERS-CoV genomes directly from respiratory samples collected from 23 confirmed MERS cases in the United Arab Emirates (UAE). These samples included cases from three nosocomial and three household clusters. The sequences were analysed for changes and relatedness with regard to the collected epidemiological data and other available MERS-CoV genomic data. Sequence analysis supports the epidemiological data within the clusters, and further, suggests that these clusters emerged independently. To understand how and when these clusters emerged, respiratory samples were taken from dromedary camels, a known host of MERS-CoV, in the same geographic regions as the human clusters. Middle East respiratory syndrome coronavirus genomes from six virus-positive animals were sequenced, and these genomes were nearly identical to those found in human patients from corresponding regions. These data demonstrate a genetic link for each of these clusters to a camel and support the hypothesis that human MERS-CoV diversity results from multiple zoonotic introductions.

Histological and immunohistochemical investigations of ovarian interstitial glands during non-breeding season in camels (Camelus dromedarius)

The aim of this was to investigate the histology and immunohistochemistry of interstitial glands during non-breeding season in camel ovaries. A total of 21 mature, non-pregnant and apparently healthy camels aged between 8 and 12 years were slaughtered. The ovaries were removed within 15 min, cleaned from adipose tissue, weighted and examined grossly. The histological preparation was made, and then, the blocks were cut at 3-5 microns thickness and stained by H&E for histological examinations. Moreover, some sections were stained with Sudan Black for lipid detection. Immunohistochemical analysis of paraffin-embedded ovarian tissues was performed to detect the localization of S-100, vimentin, progesterone receptors (PR) and oestrogen receptors (ER). Immunoreactive signals were detected using UltraVision Detection System. The results revealed that the interstitial glands were located in the cortical region and they were arranged in various arrangements either single, in couple or in groups rich in lipid droplet. All interstitial gland arrangements were enclosed by connective tissue capsules containing fibroblasts and collagenous fibres separated them from the surrounding ovarian structures. Both interstitial glands and their surrounding CT were penetrated by several blood vessels. There was a strong immunoreactive signal for S-100 in the nuclei of interstitial cells, and no signals were detected either in cells of the interstitial glands or their connective tissue with PR. We could conclude that the interstitial gland is distinct in ovary of camel and further studies are needed to elucidate its rule in steroid synthesis.

Effect of Melatonin Implants during the Non-Breeding Season on the Onset of Ovarian Activity and the Plasma Prolactin in Dromedary Camel

To examine a possible control of reproductive seasonality by melatonin, continual-release subcutaneous melatonin implants were inserted 4.5 months before the natural breeding season (October-April) into female camels (Melatonin-treated group). The animals were exposed to an artificial long photoperiod (16L:8D) for 41 days prior to implant placement to facilitate receptivity to the short-day signal that is expected with melatonin implants. The treated and control groups (untreated females) were maintained separately under outdoor natural conditions. Ovarian follicular development was monitored in both groups by transrectal ultrasonography and by plasma estradiol-17β concentrations performed weekly for 8 weeks and then for 14 weeks following implant insertion. Plasma prolactin concentrations were determined at 45 and 15 days before and 0, 14, 28, 56, and 98 days after implant insertion. Plasma melatonin concentration was determined to validate response to the artificial long photoperiod and to verify the pattern of release from the implants. Results showed that the artificial long photoperiod induced a melatonin secretion peak of significantly (P < 0.05) shorter duration (about 2.5 h). Melatonin release from the implants resulted in higher circulating plasma melatonin levels during daytime and nighttime which persisted for more than 12 weeks following implants insertion. Treatment with melatonin implants advanced the onset of follicular growth activity by 3.5 months compared to untreated animals. Plasma estradiol-17β increased gradually from the second week after the beginning of treatment to reach significantly (P < 0.01) higher concentrations (39.2 ± 6.2 to 46.4 ± 4.5 pg/ml) between the third and the fifth week post insertion of melatonin implants. Treatment with melatonin implants also induced a moderate, but significant (P < 0.05) suppressive effect on plasma prolactin concentration on the 28th day. These results demonstrate that photoperiod appears to be involved in dromedary reproductive seasonality. Melatonin implants may be a useful tool to manipulate seasonality and to improve reproductive performance in this species. Administration of subcutaneous melatonin implants during the transition period to the breeding season following an artificial signal of long photoperiod have the potential to advance the breeding season in camels by about 2.5 months.

The Suprachiasmatic Nucleus of the Dromedary Camel (Camelus dromedarius): Cytoarchitecture and Neurochemical Anatomy

In mammals, biological rhythms are driven by a master circadian clock located in the suprachiasmatic nucleus (SCN) of the hypothalamus. Recently, we have demonstrated that in the camel, the daily cycle of environmental temperature is able to entrain the master clock. This raises several questions about the structure and function of the SCN in this species. The current work is the first neuroanatomical investigation of the camel SCN. We carried out a cartography and cytoarchitectural study of the nucleus and then studied its cell types and chemical neuroanatomy. Relevant neuropeptides involved in the circadian system were investigated, including arginine-vasopressin (AVP), vasoactive intestinal polypeptide (VIP), met-enkephalin (Met-Enk), neuropeptide Y (NPY), as well as oxytocin (OT). The neurotransmitter serotonin (5-HT) and the enzymes tyrosine hydroxylase (TH) and aromatic L-amino acid decarboxylase (AADC) were also studied. The camel SCN is a large and elongated nucleus, extending rostrocaudally for 9.55 ± 0.10 mm. Based on histological and immunofluorescence findings, we subdivided the camel SCN into rostral/preoptic (rSCN), middle/main body (mSCN) and caudal/retrochiasmatic (cSCN) divisions. Among mammals, the rSCN is unusual and appears as an assembly of neurons that protrudes from the main mass of the hypothalamus. The mSCN exhibits the triangular shape described in rodents, while the cSCN is located in the retrochiasmatic area. As expected, VIP-immunoreactive (ir) neurons were observed in the ventral part of mSCN. AVP-ir neurons were located in the rSCN and mSCN. Results also showed the presence of OT-ir and TH-ir neurons which seem to be a peculiarity of the camel SCN. OT-ir neurons were either scattered or gathered in one isolated cluster, while TH-ir neurons constituted two defined populations, dorsal parvicellular and ventral magnocellular neurons, respectively. TH colocalized with VIP in some rSCN neurons. Moreover, a high density of Met-Enk-ir, 5-HT-ir and NPY-ir fibers were observed within the SCN. Both the cytoarchitecture and the distribution of neuropeptides are unusual in the camel SCN as compared to other mammals. The presence of OT and TH in the camel SCN suggests their role in the modulation of circadian rhythms and the adaptation to photic and non-photic cues under desert conditions.

Effect of genetic and nongenetic factors on chemical composition of individual milk samples from dromedary camels (Camelus dromedarius) under intensive management

The aims of the present study were to monitor the changes in gross chemical composition of individual dromedary camel milk over a 5-yr period, to provide reference values, and to determine the effect of genetic and nongenetic factors influencing camel milk composition under intensive management. A total of 1,528 lactating dromedary camels were included in the study. Animals were fed a constant diet and were milked twice a day in a herringbone parlor. Milk samples were collected at monthly intervals using a sampling device and then fat, protein, lactose, total solids (TS), and solids-nonfat (SNF) concentrations of raw camel milk were determined with an automatic milk analyzer. For each milk sample, production parameters were recorded and quantities (grams) of milk constituents were calculated. The overall mean quantity and fat, protein, lactose, SNF, and TS concentrations of the morning milk were 4.0 kg, 2.58%, 2.95%, 4.19%, 8.08%, and 10.46%, respectively. Milk quantity showed a positive correlation with lactose and a negative correlation with all other components. Parity exerted a strong effect on all milk parameters. Primiparous dromedaries (n = 60) produced less milk with higher concentrations of components than did multiparous animals (n = 1,468). Milk composition varied among the 7 breeds tested, but none of the genotypes was found to be superior to the others in this respect. We detected a significant, yet small calf sex-biased difference in milk yield and composition. Stage of lactation and season strongly influenced milk yield and all milk components. We also found a significant interaction between month postpartum (mPP) and month of the year. The concentration of all milk components decreased from 1 to 5 mPP. Later, lactose concentration and quantity continued to decrease parallel with decreasing milk production. The concentration of other components showed a temporary increase in mid lactation, from 6 to 11 mPP, and in late lactation, from 18 to 23 mPP. Mean fat, protein, SNF, and TS concentrations showed a high seasonal variation (9.5 to 28.7%), with the lowest and highest values being measured during summer and winter, respectively. This seasonal variation was independent of nutrition and may reflect an endogenous circannual rhythm. We observed a noticeable variation among years. Dromedary camels could provide a useful in vivo model to study the homeorhetic regulation of mammary cell function by endogenous and environmental factors.

Hepatitis E Virus Genotypes and Evolution: Emergence of Camel Hepatitis E Variants

Hepatitis E virus (HEV) is a major cause of viral hepatitis globally. Zoonotic HEV is an important cause of chronic hepatitis in immunocompromised patients. The rapid identification of novel HEV variants and accumulating sequence information has prompted significant changes in taxonomy of the family Hepeviridae. This family includes two genera: Orthohepevirus, which infects terrestrial vertebrates, and Piscihepevirus, which infects fish. Within Orthohepevirus, there are four species, A–D, with widely differing host range. Orthohepevirus A contains the HEV variants infecting humans and its significance continues to expand with new clinical information. We now recognize eight genotypes within Orthohepevirus A: HEV1 and HEV2, restricted to humans; HEV3, which circulates among humans, swine, rabbits, deer and mongooses; HEV4, which circulates between humans and swine; HEV5 and HEV6, which are found in wild boars; and HEV7 and HEV8, which were recently identified in dromedary and Bactrian camels, respectively. HEV7 is an example of a novel genotype that was found to have significance to human health shortly after discovery. In this review, we summarize recent developments in HEV molecular taxonomy, epidemiology and evolution and describe the discovery of novel camel HEV genotypes as an illustrative example of the changes in this field.

High Prevalence of Middle East Respiratory Coronavirus in Young Dromedary Camels in Jordan

Prevalence of Middle East respiratory syndrome coronavirus (MERS-CoV) was determined in 45 dromedary camels from two geographically separated herds in Jordan. Virus shedding was only detected in swabs obtained from the respiratory tract and primarily observed in camels younger than 3 years. MERS-CoV seroprevalence increased with age of camels. Bovine and sheep sera were seronegative. Phylogenetic analysis of partial S2 clustered the Jordanian MERS-CoV strains with contemporary MERS-CoV strains associated with nosocomial outbreaks.

Isolation and Characterization of Dromedary Camel Coronavirus UAE-HKU23 from Dromedaries of the Middle East: Minimal Serological Cross-Reactivity between MERS Coronavirus and Dromedary Camel Coronavirus UAE-HKU23

Recently, we reported the discovery of a dromedary camel coronavirus UAE-HKU23 (DcCoV UAE-HKU23) from dromedaries in the Middle East. In this study, DcCoV UAE-HKU23 was successfully isolated in two of the 14 dromedary fecal samples using HRT-18G cells, with cytopathic effects observed five days after inoculation. Northern blot analysis revealed at least seven distinct RNA species, corresponding to predicted subgenomic mRNAs and confirming the core sequence of transcription regulatory sequence motifs as 5′-UCUAAAC-3′ as we predicted previously. Antibodies against DcCoV UAE-HKU23 were detected in 58 (98.3%) and 59 (100%) of the 59 dromedary sera by immunofluorescence and neutralization antibody tests, respectively. There was significant correlation between the antibody titers determined by immunofluorescence and neutralization assays (Pearson coefficient = 0.525, p < 0.0001). Immunization of mice using recombinant N proteins of DcCoV UAE-HKU23 and Middle East respiratory syndrome coronavirus (MERS-CoV), respectively, and heat-inactivated DcCoV UAE-HKU23 showed minimal cross-antigenicity between DcCoV UAE-HKU23 and MERS-CoV by Western blot and neutralization antibody assays. Codon usage and genetic distance analysis of RdRp, S and N genes showed that the 14 strains of DcCoV UAE-HKU23 formed a distinct cluster, separated from those of other closely related members of Betacoronavirus 1, including alpaca CoV, confirming that DcCoV UAE-HKU23 is a novel member of Betacoronavirus 1.

Deciphering MERS-CoV Evolution in Dromedary Camels

The emergence of the Middle East respiratory syndrome coronavirus (MERS-CoV) poses a potential threat to global public health. Many aspects of the evolution and transmission of MERS-CoV in its animal reservoir remain unclear. A recent study provides new insights into the evolution and transmission of MERS-CoV in dromedary camels.

Detailed Anatomy of the Cranial Cervical Ganglion in the Dromedary Camel (Camelus dromedarius)

The detailed morphology and topography of the cranial cervical ganglion (CCG) with its surrounding structures were studied in 10 sides of five heads of adult one-humped camel to determine its general arrangement as well as its differences and similarities to other animals. The following detailed descriptions were obtained: (1) the bilateral CCG was constantly present caudal to cranial base at the rostroventral border of the occipital condyle over the caudolateral part of nasopharynx; (2) the CCG was always in close relations medially with the longus capitis muscle, rostrolaterally with the internal carotid artery, and caudally with the vagus nerve; and (3) the branches of the CCG were the internal carotid and external carotid nerves, jugular nerve, cervical interganglionic branch, laryngopharyngeal branch, carotid sinus branch and communicating branches to the vagus, and first spinal nerves. In conclusion, there was no variation regarding topography of dromedary CCG among the specimens, in spite of typical variations in number, and mainly in origin of nerve branches ramifying from the CCG. In comparative anatomy aspect, the close constant relations, and presence of major nerves (internal/external carotid and jugular nerves) of dromedary CCG exhibited a typical reported animal's pattern. However, the shape, structures lateral to the CCG, the origin and course pattern of external carotid and jugular nerves, the number of the major nerves branches, the communicating branches of the CCG to the spinal and cranial nerves, and the separation of most rostral parts of vagosympathetic trunk of dromedary were different from those of most reported animals.

Middle East respiratory syndrome coronavirus (MERS-CoV): evidence and speculations

In 2012, a novel human coronavirus emerged and was tentatively named "Middle East respiratory syndrome coronavirus" (MERS-CoV). The high mortality rate of MERS-CoV focused attention on the ecology of the virus. It has been found that MERS-CoV belongs to the group C lineage of the genus Betacoronavirus. Coronavirus surveillance studies in different populations of bats have suggested that they are probable reservoirs for this novel virus, and phylogenetic analysis of both the spike (S1) and RNA-dependent RNA polymerase proteins of MERS-CoV have revealed that it is related to bat viruses. Recently, the MERS-CoV and its neutralizing antibodies were detected in dromedary camels. Despite the limited number of reported cases of person-to-person transmission, the rapid evolution of the virus poses a continuous threat to humans worldwide. This paper reviews the current state of knowledge regarding the virology, clinical spectrum, evolution, diagnosis and treatment of MERS-CoV infections.

'Everybody knows', but the rest of the world: the case of a caterpillar-borne reproductive loss syndrome in dromedary camels observed by Sahrawi pastoralists of Western Sahara

BACKGROUND

The traditional knowledge of local communities throughout the world is a valuable source of novel ideas and information to science. In this study, the ethnoveterinary knowledge of Sahrawi pastoralists of Western Sahara has been used in order to put forward a scientific hypothesis regarding the competitive interactions between camels and caterpillars in the Sahara ecosystem.

METHODS

Between 2005 and 2009, 44 semi-structured interviews were conducted with Sahrawi pastoralists in the territories administered by the Sahrawi Arab Democratic Republic, Western Sahara, using a snow-ball sampling design.

RESULTS

Sahrawi pastoralists reported the existence of a caterpillar-borne reproductive loss syndrome, known locally as duda, affecting their camels. On the basis of Sahrawi knowledge about duda and of a thorough literature review, we built the hypothesis that: 1) caterpillars of the family Lasiocampidae (genera Lasiocampa, Psilogaster, or Streblote) have sudden and rare outbreaks on Acacia treetops in the Western Sahara ecosystem after heavy rainfall; 2) during these outbreaks, camels ingest the caterpillars while browsing; 3) as a consequence of this ingestion, pregnant camels have sudden abortions or give birth to weaklings. This hypothesis was supported by inductive reasoning built on circumstantiated evidence and analogical reasoning with similar syndromes reported in mares in the United States and Australia.

CONCLUSIONS

The possible existence of a caterpillar-borne reproductive loss syndrome among camels has been reported for the first time, suggesting that such syndromes might be more widespread than what is currently known. Further research is warranted to validate the reported hypothesis. Finally, the importance of studying folk livestock diseases is reinforced in light of its usefulness in revealing as yet unknown biological phenomena that would deserve further investigation.