First record of nasopharyngeal myiasis caused by Cephalopina titillator (Clark, 1816) in camel (Camelus dromedarius Linnaeus, 1758) in Uzbekistan

Nasopharyngeal myiasis caused by the camel nasal bot, Cephalopina titillator, is very common in old world camelids and is usually found at necropsy or during meat inspection. Herein we report massive infection with C. titillator in a 9 years old female one-humped camel slaughtered on February 18, 2024 in the village of Kizil Uy, Nukus District, Republic of Karakalpakstan, northwestern Uzbekistan. A total of 69 larvae: 20 first stage larva (28.9%), 31  second stage larva (44.9%), and 18 third stage larva (26.0%) were detected in the nasal passages and pharynx of the camel. Morphological and morphometrical characters of all larval stages are illustrated and detailed in this article. To our knowledge this is the first record of camel nasal bot infestation in Uzbekistan. Future epidemiological studies are needed to shed light on the prevalence, seasonal fluctuation, clinical impact and economic burden of nasopharyngeal myiasis in dromedary camels of the country.

Development and validation of the Axiom-MaruPri SNP chip for genetic analyses of domesticated old world camelids

Camels play a crucial socio-economic role in sustaining the livelihoods of millions in arid and semi-arid regions. They possess remarkable physiological attributes which enable them to thrive in extreme environments, and provide a source of meat, milk and transportation. With their unique traits, camels embody an irreplaceable source of untapped genomic knowledge. This study introduces Axiom-MaruPri, a medium-density SNP chip meticulously designed and validated for both Camelus bactrianus and Camelus dromedarius. Comprising of 182,122 SNP markers, derived from the re-sequenced data of nine Indian dromedary breeds and the double-humped Bactrian camel, this SNP chip offers 34,894 markers that display polymorphism in both species. It achieves an estimated inter-marker distance of 14 Kb, significantly enhancing the coverage of the camel genome. The medium-density chip has been successfully genotyped using 480 camel samples, achieving an impressive 99 % call rate, with 96 % of the 182,122 SNPs being highly reliable for genotyping. Phylogenetic analysis and Discriminant Analysis of Principal Components yield clear distinctions between Bactrian camels and dromedaries. Moreover, the discriminant functions substantially enhance the classification of dromedary camels into different breeds. The clustering of various camel breeds reveals an apparent correlation between geographical and genetic distances. The results affirm the efficacy of this SNP array, demonstrating high genotyping precision and clear differentiation between Bactrian and dromedary camels. With an enhanced genome coverage, accuracy and economic efficiency the Axiom_MaruPri SNP chip is poised to advance genomic breeding research in camels. It holds the potential to serve as an invaluable genetic resource for investigating population structure, genome-wide association studies and implementing genomic selection in domesticated camelid species.

Camel urine as a potential source of bioactive molecules showing their efficacy against pathogens: A systematic review

Camels are highly suited for severe desert conditions and able to provide most of the natural products like urine, which has been used as alternative medicine to treat diverse infections and disorders. There is, however, a shortage and paucity of scientific reviews highlighting the antifungal, antibacterial and antiviral effects of camel urine. By better understanding its antimicrobial characteristics, our overarching aim is to provide an exhaustive overview of this valuable natural product by synthesizing and summarizing data on the efficacy of this biofluid and also describing the potential substances exhibiting antimicrobial properties. We searched three databases in order to point out relevant articles (Web of Science, Scopus and Google Scholar) until December 2022. Research articles of interest evaluating the antimicrobial effects of camel urine were selected. Overall, camel urine furnished promising antibacterial activities against gram-positive bacteria, namely Staphylococcus aureus (30 mm), Bacillus cereus (22 mm), Bacillus subtilis (25 mm) and Micrococcus luteus (21 mm), as well as gram-negative bacteria, especially Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Enterobacter cloacae, and Salmonella spp., without forgetting its efficiency on Mycobacterium tuberculosis as well. The excretion also showed its potency against H1N1 virus, vesicular stomatitis virus and middle east respiratory syndrome coronavirus. Similarly, the camel urine featured strong antifungal activity against Candida albicans, Aspergillus niger, Aspergillus flavus and dermatophytes with a minimal inhibitory concentration of 0.625 μg/ml against Trichophyton violaceum, 2.5 μg/ml against Microsporum canis and 1.25 μg/ml against Trichophyton rubrum and Trichophyton mentagrophytes. This comprehensive review will be valuable for researchers interested in investigating the potential of camel urine in the development of novel broad-spectrum key molecules targeting a wide range of drug-resistant pathogenic microorganisms.

First serological evidence of MERS-CoV in dromedary camels from Algeria

Middle East Respiratory Syndrome (MERS) is a zoonotic disease. Dromedary camel is responsible of its transmission to humans. Accordingly, several human cases have been reported worldwide with a high mortality rate. In Algeria, no data reported on MERS prevalence in camels. This is a first seroprevalence study MERS-CoV in Algerian dromedaries. A total of 87 camel blood samples from EL -MENIAA and Ghardaia, were analyzed by anti-MERS-CoV IgG ELISA camel. The seroprevalence was 64 % and it significantly increases with age. Larger serological and molecular screening is needed to precisely determine the rate of MERS active circulation among Algerian dromedary population.

Comparison of pregnancy outcomes following the transfer of early-developmental stage embryos and blastocysts produced by somatic cell nuclear transfer in Camelus dromedarius

The embryonic stage, site of embryo transfer in the reproductive tract of the surrogate, and embryo transfer method are important for the successful production of offspring. In the present study, there was comparison of pregnancy rates in camels following the surgical transfer of early-developmental stage embryos at Day 2 and transvaginal transfer of blastocysts at Day 7. Embryos were produced by somatic cell nuclear transfer using in vivo-matured oocytes and ear fibroblasts as donor cells. A total of 305 oocytes were collected from 27 donors, among which 275 oocytes were in metaphase II. In Group A, 110 oocytes were reconstructed, 78 fused oocytes were cultured for 2 days, and 37 early-developmental stage embryos were transferred into 13 surrogates. In Group B, 165 oocytes were utilized, 117 fused oocytes were cultured for 7 days, and 24 blastocysts were trans-vaginally transferred into 12 surrogates. Pregnancy was determined when there was an increase in serum progesterone concentrations and was confirmed using real-time ultrasonography. Microsatellite analysis was performed to confirm the parentage of offspring. Two live births occurred in Groups A and B (live birth rate of 15.4% and 16.7%, respectively). Results indicate both early-developmental stage embryos and blastocysts produced by somatic cell nuclear transfer using in vivo-matured oocytes can lead to live births in camel with similar efficiency. It, therefore, is recommended that trans-vaginal blastocyst transfer be utilized for camels considering the pregnancy and live birth rates, ease of the transfer procedure and comfort and safety of surrogates.

Review of milk let-down in camels and proposition of a milk recording method

The aim of this article was to review the milk let-down in camels and to propose a simple milk recording method. Milking of camels generally starts between 1 and 3 months postpartum. The udder is stimulated for 0.5 to 2 min by either calf suckling or hand massaging to induce the milk let-down. About 40% of daily milk yield is consumed by the calf before and after milking. The best interval between milking is 8-12 h. Lactation length is in the range 8-18 months, and the mean total milk yield is 1000-4000 kg. Peak yield of 4 to 10 kg is attained between 2 and 7 months post calving, and persistency is greater than 85%. The proposed milk recording method for camels has been adapted from ICAR's procedures. The milking (manual or machine) starts after a suckling period of 1 month. Before each milking, the udder is stimulated for 1 min, either by calf suckling or by hand massaging. The milk recording interval is 36 days. The first test recording must take place within 75 days following the end of the suckling period. Milk yield recorded is the milk off-take or milked only. The lactation period corresponds to the milking length. Records are standardized to the reference lactation of 335 days. At each recording day, milk yields are recorded and milk samples are collected alternatively at either morning or evening milking. It was concluded that using this method, a sound milk recording database will be built for camels.

Nucleotide diversity of functionally different groups of immune response genes in Old World camels based on newly annotated and reference-guided assemblies

Background

Immune-response (IR) genes have an important role in the defense against highly variable pathogens, and therefore, diversity in these genomic regions is essential for species’ survival and adaptation. Although current genome assemblies from Old World camelids are very useful for investigating genome-wide diversity, demography and population structure, they have inconsistencies and gaps that limit analyses at local genomic scales. Improved and more accurate genome assemblies and annotations are needed to study complex genomic regions like adaptive and innate IR genes.

Results

In this work, we improved the genome assemblies of the three Old World camel species – domestic dromedary and Bactrian camel, and the two-humped wild camel – via different computational methods. The newly annotated dromedary genome assembly CamDro3 served as reference to scaffold the NCBI RefSeq genomes of domestic Bactrian and wild camels. These upgraded assemblies were then used to assess nucleotide diversity of IR genes within and between species, and to compare the diversity found in immune genes and the rest of the genes in the genome. We detected differences in the nucleotide diversity among the three Old World camelid species and between IR gene groups, i.e., innate versus adaptive. Among the three species, domestic Bactrian camels showed the highest mean nucleotide diversity. Among the functionally different IR gene groups, the highest mean nucleotide diversity was observed in the major histocompatibility complex.

Conclusions

The new camel genome assemblies were greatly improved in terms of contiguity and increased size with fewer scaffolds, which is of general value for the scientific community. This allowed us to perform in-depth studies on genetic diversity in immunity-related regions of the genome. Our results suggest that differences of diversity across classes of genes appear compatible with a combined role of population history and differential exposures to pathogens, and consequent different selective pressures.

Mitochondrial DNA variation and phylogeography of Old World camels

Objective

Old World camels are a valuable genetic resource for many countries around the world due to their adaptation to the desert environment. At present, Old World camels have encountered the challenge of unprecedented loss of genetic resources. Through our research, we would reveal the population structure and genetic variation in Old World camel populations, which provides a theoretical basis for understanding the germplasm resources and origin and evolution of different Old World camel populations.

Methods

In the present study, we assessed mtDNA control region sequences of 182 individuals from Old World camels to unravel genetic diversity, phylogeography, and demographic dynamics.

Results

Thirty-two haplotypes confirmed by 54 polymorphic sites were identified in the 156 sequences, which included 129 domestic and 27 wild Bactrian camels. Meanwhile, 14 haplotypes were defined by 47 polymorphic sites from 26 sequences in the dromedaries. The wild Bactrian camel population showed the lowest haplotype and nucleotide diversity, while the dromedaries investigated had the highest. The phylogenetic analysis suggests that there are several shared haplotypes in different Bactrian camel populations, and that there has been genetic introgression between domestic Bactrian camels and dromedaries. In addition, positive values of Tajima’s D and Fu’s Fs test demonstrated a decrease in population size and/or balancing selection in the wild Bactrian camel population. In contrast, the negative values of Tajima’s D and Fu’s Fs test in East Asian Bactrian camel populations explained the demographic expansion and/or positive selection.

Conclusion

In summary, we report novel information regarding the genetic diversity, population structure and demographic dynamics of Old World camels. The findings obtained from the present study reveal that abundant genetic diversity occurs in domestic Bactrian camel populations and dromedaries, while there are low levels of haplotype and nucleotide diversity in the wild Bactrian camel population.

Dromedary camel: A model of heat resistant livestock animal

Camels are highly adapted to harsh environments. The dromedary camel is adapted to a wide range of arid and semi-arid conditions. The aim of the present paper is to review some of the key adaptation characteristics of the dromedary and how they affect reproductive patterns. Special attention is given to the reproductive seasonality and interaction between lactation and reproduction. Adaptive mechanisms are described including some of the recent molecular aspects with respect to heat shock protein expression in camels.

Parasitological, serological and molecular survey of camel trypanosomiasis in Somalia

Background

Camel trypanosomiasis or surra is of great concern in Somalia, since the country possesses the largest one-humped camel (Camelus dromedarius) population in the world. Civil war in Somalia has resulted in the destruction of educational, research, economic and social structures, making the country scores very low for most humanitarian indicators. Previous studies on detection of Trypanosoma species in Somali camels have only been performed during the 1990s using standard trypanosome detection methods (STDM). Considering the lack of state-of-the-art knowledge on camel trypanosomiasis in Somalia, the present study aimed to assess the prevalence of Trypanosoma spp. in three districts of Somalia.

Methods

A total of 182 blood samples from C. dromedarius from nomadic and dairy farms were evaluated using STDM, serological (CATT/T. evansi) and molecular (ITS1-PCR) methods.

Results

All samples were negative for Trypanosoma spp. by STDM. A total of 125/182 (68.7%, 95% CI: 61.4–75.3%) camels were seropositive for T. evansi by CATT/T. evansi. Camels reared in nomadic system were more likely to be seropositive for T. evansi than those under dairy production system (OR: 5.6, 95% CI: 2.1–15.2, P = 0.0001). Five out of 182 (2.7%, 95% CI: 0.9–6.3%) camels tested positive for Trypanosoma sp. by ITS1-PCR. Sequencing of the ITS1 region of the Trypanosoma species detected herein revealed that camels were infected with T. evansi and T. simiae.

Conclusions

Trypanosoma evansi is highly prevalent in camels from the Banadir region of Somalia, particularly in nomadic herds. To our knowledge, this is the first study to confirm infections with T. evansi and T. simiae in Somali camels through DNA sequencing. Our data highlight the need for implementation of adequate control measures aiming to reduce the impact on camel production in the country.

Comparative fatty acids composition and cholesterol content in Bactrian (Camelus bactrianus) and dromedary camel (Camelus dromedarius) meat

The present study is aimed at comparing the fatty acid profiles, cholesterol, and atherogenicity index of Bactrian and dromedary camel meat by using discriminant analysis to identify the more discriminating fatty acids. Six muscles were sampled from nine Bactrian and nine dromedary camels and analyzed for fatty acid parameters and cholesterol content. The mean fatty acid profiles differed in higher proportion between species than between muscles. The main discriminating fatty acids between species (100% well-classed samples) were C15:0, C17:1, C14:1, C20:0, and C18:0. A significant difference was also observed in cholesterol content, with more cholesterol in Bactrian meat (53.6 ± 12.5 mg/100 g) compared to dromedary meat (49.4 ± 11.2 mg/100 g). However, the atherogenicity index was lower in Bactrian meat (1.196 ± 0.148) than in dromedary meat (1.379 ± 0.109). Despite the dietetic interest in camel meat due to its low cholesterol and low-fat content, the high atherogenicity index compared to other red meat appeared as an unfavorable argument.

Vector-borne bacteria in blood of camels in Iran: New data and literature review

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Information about vector-borne bacteria of camels is scarce.

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Anaplasmataceae, SFG rickettsiae, Bartonella and Borrelia were investigated in blood of 200 dromedary camels of Iran.

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PCR results revealed 30 animals (15%) to be infected with Anaplasmataceae bacteria.

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BlastN® analysis of positive samples revealed identity with “Candidatus Anaplasma camelii” isolates.

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This paper reviews the current knowledge on camels’ tick-borne bacteria including microscopy, serology and molecular studies.

Despite close association between camels and humans, molecular based studies on vector-borne pathogens infecting camels are scarce compared to other animals in Iran. The current study was carried out to investigate the occurrence of vector-borne bacteria in the blood of dromedaries by molecular tools. A total of 200 peripheral blood samples were collected from apparently healthy animals. Microscopic examination was performed on Giemsa-stained blood smears, and drops of blood were spotted on Whatman FTA^® cards for molecular analyses. Genomic DNA was extracted from the cards, and PCR amplification followed by sequencing of positive samples was carried out for the detection of Anaplasmataceae, spotted fever group (SFG) rickettsiae, Bartonella spp. and Borrelia spp. Intra-cytic forms of any blood pathogens could not be detected by light microscopy. PCR results revealed 30 animals (15%) to be infected with Anaplasmataceae bacteria. Analyses of sequences revealed a strain of Anaplasma sp. identical to Candidatus Anaplasma camelii isolated from camels, cattle and deer in Asia and Africa. Neither SFG rickettsiae, nor Borrelia or Bartonella species were found. Further studies for determining epidemiological role of camels and its zoonotic potential are recommended. This paper reviews the current knowledge on camels’ tickborne bacteria including microscopy, serology and molecular studies.

Comparison of body weight estimation equations for camels (Camelus dromedarius)

The objective of the present study was to evaluate the accuracy of six different equations for weight estimation of camels using body measurements as chest girth, height at withers, and hump girth in order to identify the most reliable equation for use in the field. The prediction equations that were compared were those of Boué Revue d'Élevage et de Médecine vétérinaire des Pays tropicaux 3 (1), 13-16, 1949; Graber Revue d'Élevage et de Médecine vétérinaire des Pays tropicaux, 19, 527-543, 1966; Wilson Tropical Animal Health and Production, 10, 19-25, 1978; Field Proceedings of the Khartoum workshop on camels V1, 209-230, 1979; Bucci et al. Indian Veterinary Journal, 61, 26-30, 1984; and Yagil A Handbook for Camel Breeding, 1994 noticed as BW1, BW2, BW3, BW4, BW5, and BW6, respectively. The dataset used for this evaluation is the one published by Boué Revue d'Élevage et de Médecine vétérinaire des Pays tropicaux 3 (1), 13-16, 1949. Range observed in predicted weight, mean prediction error (MPE), residual mean square (MSE), mean square prediction error (MSPE), coefficient of determination (CD), and concordance correlation coefficient (CCC) were used to assess the different body weight prediction equations. Moreover, paired t tests were applied to compare the true weight and each of the six predicted weights. From the six prediction equations, range observed in predicted weights varied from 193 to 237 kg, MSE from 335.5 to 806.1, MPE from - 129.8 to 24.7 kg, MSPE from 329.4 to 17,617.1, CD from 0.753 to 0.867, and CCC from 0.162 to 0.928. BW4 presented the best prediction results, showing a low MSE, high CD and CCC, whereas BW3 yielded the least accurate estimate of body weight and had weak statistics. The study concluded that BW4 is the most reliable of all equations to estimate camel's body weight, whereas BW3 is less reliable and its use must be discontinued.

Circannual changes in major chemical composition of bulk dromedary camel milk as determined by FT-MIR spectroscopy, and factors of variation

We monitored the major chemical composition of bulk dromedary camel milk by FT-MIR spectroscopy over a 5-year period. The results highly correlated with those determined with reference methods (r > 0.985, p < 0.001). Production parameters showed significant (p < 0.001) seasonal and yearly changes. The overall mean fat, protein, lactose, solids-not-fat, and total solids concentrations of bulk dromedary camel milk were 2.87%, 2.94%, 4.15%, 8.00%, and 10.69%, respectively. Month of the year, year of the study, and level of production had a strong influence on bulk milk chemical composition and yield of milk components; however, the relative effect of season on composition was greater (proportion of variance app. 50%) compared to that of other factors of variation. The highest and lowest values were measured during winter and summer, respectively. Circannual variation in major milk components was associated with environmental conditions (photoperiod, temperature), whereas it was independent of nutritional factors.

Glycoconjugates pattern and chemosensory cells in the camel respiratory mucosa: Lectin and immunohistochemical studies

The glycoconjugates pattern of acidic secretions and distribution of chemosensory cells (SCCs) in the respiratory mucosa of dromedary camels were analyzed so as to identify their functional role. Secretions of the goblet cells and mucous glandular cells were analyzed to evaluate the variety of sugar chains, focusing on the acidic glycoconjugates. Using lectin histochemistry, WGA, STL, DBA, SBA, VVA and RCA-120 intensely bound to the goblet cells. PNA and ECL labeled the goblet cells with moderate intensity. While, s-WGA, UEA-I faintly bound to them. Lectins bound to the glycocalyx: WGA, LEL, STL, DSL, DBA, SBA, VVA, RCA-120, ECL and PHA-L (tetra- and tri-antennary N-glycans). The mucous secretory cells reacted with: WGA, s-WGA, STL, DBA, SBA, ECL and Con A. Glycoconjugates secreted by the camel respiratory mucosa are rich in sialomucins, glucosaminy-lated residuals with some galactosyl/galactosaminylated residues; few L-fucose and mannosylated sugar residues are also included. For identification of SCCs, the camel respiratory mucosa was immunostained with phospholipase C-β2 (PLC-β2), a taste signaling marker. Several PLC-β2 immunoreactive cells were detected in camel respiratory epithelium. Finally, prevalence of sialomucins and SCCs which can respond to noxious chemicals may suggest a vital role in optimizing physiological and pathological reactions in camel respiratory mucosa.

Isolation and characterization of the trophectoderm from the Arabian camel (Camelus dromedarius)

We isolated and characterized trophoblast from in vivo-derived camel embryos and compared with embryonic stem-like cells. Camel embryos were flushed on day 8 post-insemination and used to derive trophectoderm and embryonic stem-like cells under feeder-free culture conditions using a basement membrane matrix. Embryos were evaluated for the expression of POU5F1, MYC, KLF4, SOX2, CDX2, and KRT8 mRNA transcripts by relative quantitative polymerase chain reaction. Camel embryos grew and expanded to ∼4.5 mm and maintained their vesicular shape in vitro for 21 days post-insemination. Trophoblast and embryonic stem-like cell lines grew under feeder-free culture conditions and showed distinct morphological criteria and normal chromosomal counts. Embryonic stem-like cells showed positive staining in the alkaline phosphatase reaction. Trophoblast cells showed a significant increase in CDX2, KRT8, KLF4, and SOX2 expression compared with embryonic stem-like cells and whole embryos. Embryonic stem-like cells showed a significant decrease in CDX2 expression and increase in SOX2 and KRT8 expression compared to embryonic expression. POU5F1 and MYC expression showed no difference between embryos and both cell lines. We characterized embryo survival in vitro, particularly the derivation of trophectoderm and embryonic stem-like cells, providing a foundation for further analysis of early embryonic development and placentation in camels.

Scrotal granulomatous aspergillosis in a dromedary camel (Camelus dromedarius)

BACKGROUND

This report describes a case of primary subcutaneous aspergillosis in a 7-year-old neutered male dromedary camel (Camelus dromedarius).

CASE PRESENTATION

The animal developed a large nodular lesion in the right scrotum two years after surgical intervention for neutering. The mass had a firm consistency and was painful at palpation. Histopathology revealed dermal granulomatous inflammation with a necrotic centre, surrounded by plasma cells, macrophages, neutrophils, and sparse fungal hyphae characterised by parallel cell walls, distinct septa, and dichotomous branching. Fungal culture was not performed, but a panel of mono- and polyclonal antibodies specific for different fungal genera identified the hyphae as Aspergillus sp.

CONCLUSIONS

The occurrence of subcutaneous lesions is a rare manifestation of aspergillosis in animals, and this appears to be the first case reported in the dromedary camel.

Evaluation of a panel of antibodies for the immunohistochemical identification of immune cells in paraffin-embedded lymphoid tissues of new- and old-world camelids

Different species of camelids play an important role in the epidemiology of various emerging infectious diseases such as Middle East respiratory syndrome. For precise investigations of the immunopathogenesis in these host species, appropriate immunohistochemical markers are highly needed in order to phenotype distinct immune cells populations in camelids. So far, specific immunohistochemical markers for camelid immune cells are rarely commercially available, and cross-reactivity studies are restricted to the use of frozen dromedary tissues. To bridge this gap, 14 commercially available primary antibodies were tested for their suitability to demonstrate immune cell populations on formalin fixed paraffin-embedded (FFPE) tissue sections of dromedaries, Bactrian camels, llamas, and alpacas in the present study. Out of these, 9 antibodies directed against CD3, CD20, CD79α, HLA-DR, Iba-1, myeloid/histiocyte antigen, CD204, CD208, and CD68 antigen exhibited distinct immunoreaction patterns to certain camelid immune cell subsets. The distribution of these antigens was comparatively evaluated in different anatomical compartments of thymus, spleen, mesenteric, and tracheobronchial lymph nodes. The presented results will provide a basis for further investigations in camelids, especially with respect to the role of the immune response in certain infectious diseases, which harbor a considerable risk to spill over to other species.

Middle East respiratory syndrome (MERS) coronavirus and dromedaries

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Middle East Respiratory Syndrome (MERS) is a zoonotic viral disease transmissible from dromedaries to human beings.

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MERS coronavirus (MERS-CoV) infection in dromedaries is usually asymptomatic but mild respiratory signs may occur.

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No MERS-CoV or antibodies against the virus have been detected in camelids other than dromedaries.

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Dromedaries acquire MERS-CoV at less than 1 year of age and 100% of adult dromedaries are seropositive for the virus.

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MERS-CoV in dromedaries is detected by virus isolation, quantitative reverse transcriptase-PCR or antigen detection.

Middle East Respiratory Syndrome (MERS) is a zoonotic viral disease that can be transmitted from dromedaries to human beings. More than 1500 cases of MERS have been reported in human beings to date. Although MERS has been associated with 30% case fatality in human beings, MERS coronavirus (MERS-CoV) infection in dromedaries is usually asymptomatic. In rare cases, dromedaries may develop mild respiratory signs. No MERS-CoV or antibodies against the virus have been detected in camelids other than dromedaries. MERS-CoV is mainly acquired in dromedaries when they are less than 1 year of age, and the proportion of seropositivity increases with age to a seroprevalence of 100% in adult dromedaries. Laboratory diagnosis of MERS-CoV infection in dromedaries can be achieved through virus isolation using Vero cells, RNA detection by real-time quantitative reverse transcriptase-PCR and antigen detection using respiratory specimens or serum. Rapid nucleocapsid antigen detection using a lateral flow platform allows efficient screening of dromedaries carrying MERS-CoV. In addition to MERS-CoV, which is a lineage C virus in the Betacoronavirus (betaCoV) genus, a lineage B betaCoV and a virus in the Alphacoronavirus (alphaCoV) genus have been detected in dromedaries. Dromedary CoV UAE-HKU23 is closely related to human CoV OC43, whereas the alphaCoV has not been detected in human beings to date.

Middle East respiratory syndrome coronavirus (MERS-CoV): animal to human interaction

The Middle East respiratory syndrome coronavirus (MERS-CoV) is a novel enzootic betacoronavirus that was first described in September 2012. The clinical spectrum of MERS-CoV infection in humans ranges from an asymptomatic or mild respiratory illness to severe pneumonia and multi-organ failure; overall mortality is around 35.7%. Bats harbour several betacoronaviruses that are closely related to MERS-CoV but more research is needed to establish the relationship between bats and MERS-CoV. The seroprevalence of MERS-CoV antibodies is very high in dromedary camels in Eastern Africa and the Arabian Peninsula. MERS-CoV RNA and viable virus have been isolated from dromedary camels, including some with respiratory symptoms. Furthermore, near-identical strains of MERS-CoV have been isolated from epidemiologically linked humans and camels, confirming inter-transmission, most probably from camels to humans. Though inter-human spread within health care settings is responsible for the majority of reported MERS-CoV cases, the virus is incapable at present of causing sustained human-to-human transmission. Clusters can be readily controlled with implementation of appropriate infection control procedures. Phylogenetic and sequencing data strongly suggest that MERS-CoV originated from bat ancestors after undergoing a recombination event in the spike protein, possibly in dromedary camels in Africa, before its exportation to the Arabian Peninsula along the camel trading routes. MERS-CoV serosurveys are needed to investigate possible unrecognized human infections in Africa. Amongst the important measures to control MERS-CoV spread are strict regulation of camel movement, regular herd screening and isolation of infected camels, use of personal protective equipment by camel handlers and enforcing rules banning all consumption of unpasteurized camel milk and urine.

Effects of age and period of fattening on carcass and non-carcass characteristics of one-humped camels

This study was conducted to compare the carcass characteristics and quantity of carcass and non-carcass components of 2- and 3-year-old male camels fattened for either 3 or 6 months. Twelve 2-year-old camels with an average body live weight of 268.5 ± 21.4 kg and twelve 3-year-old camels with an average body live weight of 307.5 ± 29.9 kg were used in a completely randomized design with a 2 × 2 factorial arrangement. For carcass analysis, three camels from each group were selected and slaughtered. The results showed that camel age and fattening period had no significant effect on average daily gain (ADG). Older camels and a longer fattening period resulted in heavier hot and cold carcass weights. Three-year-old camels had a higher dressing percentage compared to 2-year-old camels, regardless of the period of fattening. Analysis of non-carcass components showed that the heaviest component was the hide and 2-year-old camels fattened for 90 days had the greatest weight of hide as percentage of cold carcass weight. Total muscle weight was greater for the 3-year-old camels compared to the 2-year-old ones, regardless of the fattening period, and camels fattened for 180 days had heavier weight than those fattened for 90 days, regardless of age at fattening. However, the greatest weight of total muscle was detected in camels at 2 years of age fattened for 180 days when it was expressed as percentage of carcass weight. The highest and the lowest total fat content as kilogram or as percentage of cold carcass was observed in 3-year-old camels fattened for 180 days and 2-year-old camels fattened for 180 days, respectively. Our results suggested that the best age for slaughtering is 2 years old with the fattening period of 180 days.

Middle East Respiratory Syndrome Coronavirus (MERS-CoV) origin and animal reservoir

Middle East Respiratory Syndrome-Coronavirus (MERS-CoV) is a novel coronavirus discovered in 2012 and is responsible for acute respiratory syndrome in humans. Though not confirmed yet, multiple surveillance and phylogenetic studies suggest a bat origin. The disease is heavily endemic in dromedary camel populations of East Africa and the Middle East. It is unclear as to when the virus was introduced to dromedary camels, but data from studies that investigated stored dromedary camel sera and geographical distribution of involved dromedary camel populations suggested that the virus was present in dromedary camels several decades ago. Though bats and alpacas can serve as potential reservoirs for MERS-CoV, dromedary camels seem to be the only animal host responsible for the spill over human infections.

A proposal of linear assessment scheme for the udder of dairy camels (Camelus dromedarius L.)

Digital images from the left side of the mammary gland of 146 multiparous lactating dromedary camels in mid lactation and managed under intensive conditions were obtained immediately before milking and used to build up a reference scheme for the morphological evaluation of camel mammary glands. A 5-point linear scoring scheme (with 0.5-point accuracy) was subsequently generated based on five mammary traits (udder, depth and floor inclination, teats, shape, length, and width). Results showed that Arabian dairy camels had voluminous udders with large-sized teats. Most common udder shape was globular (47.3 %), followed by the pear (34.3 %) and pendulous (18.4 %) shapes. Conical- or funnel-shaped teats (60.9 %) were the most frequent, followed by cylindrical- (29.5 %) and blew-up (9.6 %)-shaped teats. The observed variation in the udder and teat measurements, as well as in typology, attested that dromedary camels need especially large milking clusters to improve their machine milkability. Assessment of the previously indicated digital images according to the proposed linear scoring scheme, performed by 3 independent operators showed that the overall means were close to 3.00 points (values between 2.45 and 3.62), and the standard deviations were close to 0.76 points (values between 0.58 and 0.94). Moderate repeatability between operators (r > 0.69) was obtained for udder depth and floor inclination, indicating that training of operators, as well as improvements in the definition of traits should be considered in future studies. Further research is needed to validate the proposed linear scoring system in different stages of lactation and parities using a large number of camels.

The differentiation of camel breeds based on meat measurements using discriminant analysis

The meat productivity of camel in the tropics is still under investigation for identification of better meat breed or type. Therefore, four one-humped Saudi Arabian (SA) camel breeds, Majaheem, Maghateer, Hamrah, and Safrah were experimented in order to differentiate them from each other based on meat measurements. The measurements were biometrical meat traits measured on six intact males from each breed. The results showed higher values of the Majaheem breed than that obtained for the other breeds except few cases such dressing percentage and rib-eye area. In differentiation analysis, the most discriminating meat variables were myofibrillar protein index, meat color components (L* and a*, b*), and cooking loss. Consequently, the Safrah and the Majaheem breeds presented the largest dissimilarity as evidenced by their multivariate means. The canonical discriminant analysis allowed an additional understanding of the differentiation between breeds. Furthermore, two large clusters, one formed by Hamrah and Maghateer in one group along with Safrah. These classifications may assign each breed into one cluster considering they are better as meat producers. The Majaheem was clustered alone in another cluster that might be a result of being better as milk producers. Nevertheless, the productivity type of the camel breeds of SA needs further morphology and genetic descriptions.

Scarabaeus cristatus (Coleoptera: Scarabaeidae) as intermediate host of Physocephalus dromedarii (Nematoda: Spirocercidae)--a contribution to the epidemiology of camel physocephalidosis

In UAE, camel Physocephalus dromedarii was diagnosed for the first time in 2011 in dromedaries from a farm that previously had imported animals from foreign countries. The large scarab beetle, Scarabaeus cristatus, was found to be the major intermediate host for this parasite in Dubai. A total of 638 specimens of S. cristatus were collected and examined for the presence of third-stage larvae of nematode larvae at two sites in the Dubai Emirate (Emirates Industry for Camel Milk and Products and horse endurance training track) within a distance of 15 km. Third-stage larvae of P. dromedarii were detected in 94 and 97 % of beetles collected from the territory of the camel milk farm and the endurance training track, respectively. In addition to third-stage larvae, 264 beetles contained second-stage larvae. Only four beetles were infected with other than P. dromedarii larvae. The average larval burden in beetles from camel milk farm was significantly higher compared to those in beetles collected from the other site (1538 vs. 697). Comparison of larval burdens in juvenile and adult beetles collected at the camel milk farm showed a significantly higher intensity in adult specimens (501 vs. 1734) while in beetles found on the horse endurance track, larval burdens were comparable (548 vs. 858). The results suggest that S. cristatus become infected at the camel milk farm, and in search for other sources of food, they fly to places where they were found feeding on feces of other animals.

Middle East respiratory syndrome coronavirus "MERS-CoV": current knowledge gaps

The Middle East respiratory syndrome coronavirus (MERS-CoV) that causes a severe lower respiratory tract infection in humans is now considered a pandemic threat to the Gulf region. Since its discovery in 2012, MERS-CoV has reached 23 countries affecting about 1100 people, including a dozen children, and claiming over 400 lives. Compared to SARS (severe acute respiratory syndrome), MERS-CoV appears to kill more people (40% versus 10%), more quickly, and is especially more severe in those with pre-existing medical conditions. Most MERS-CoV cases (>85%) reported thus far have a history of residence in, or travel to the Middle East. The current epidemiology is characterised by slow and sustained transmission with occasional sparks. The dromedary camel is the intermediate host of MERS-CoV, but the transmission cycle is not fully understood. In this current review, we have briefly summarised the latest information on the epidemiology, clinical features, diagnosis, treatment and prevention of MERS-CoV especially highlighting the knowledge gaps in its transmission dynamics, diagnosis and preventive strategy.

Characteristics of the somatic hypermutation in the Camelus dromedarius T cell receptor gamma (TRG) and delta (TRD) variable domains

In previous reports, we had shown in Camelus dromedarius that diversity in T cell receptor gamma (TRG) and delta (TRD) variable domains can be generated by somatic hypermutation (SHM). In the present paper, we further the previous finding by analyzing 85 unique spleen cDNA sequences encoding a total of 331 mutations from a single animal, and comparing the properties of the mutation profiles of dromedary TRG and TRD variable domains. The transition preference and the significant mutation frequency in the AID motifs (dgyw/wrch and wa/tw) demonstrate a strong dependence of the enzymes mediating SHM in TRG and TRD genes of dromedary similar to that of immunoglobulin genes in mammals. Overall, results reveal no asymmetry in the motifs targeting, i.e. mutations are equally distributed among g:c and a:t base pairs and replacement mutations are favored at the AID motifs, whereas neutral mutations appear to be more prone to accumulate in bases outside of the motifs. A detailed analysis of clonal lineages in TRG and TRD cDNA sequences also suggests that clonal expansion of mutated productive rearrangements may be crucial in shaping the somatic diversification in the dromedary. This is confirmed by the fact that our structural models, computed by adopting a comparative procedure, are consistent with the possibility that, irrespective of where (in the CDR-IMGT or in FR-IMGT) the diversity was generated by mutations, both clonal expansion and selection seem to be strictly related to an enhanced structural stability of the γδ subunits.

Evaluation of the microbial quality of fresh ejaculates of camel (Camelus dromedarius) semen

A series of five factorial arranged experiments were conducted to investigate the effect of different management during semen collection on the microbial quality (bacterial load, type of microbes and frequency of isolation) of dromedaries' semen. Microbial analysis of seventy-nine fresh ejaculates from twenty-two camels showed the presence of nine variant colonies. The most prevalent organisms in the dromedary semen were species of Staphylococcus, Bacillus and Streptococcus. One yeast species was represented among the isolates. The middle aged camels (9-13 years) had significantly (P>0.05) higher mean bacterial loads than young (4-8 years) and old aged (14-18 years) animals. The mean bacterial populations of ejaculates collected by an electro-ejaculator were significantly (P>0.05) higher than those collected by an artificial vagina. Candida spp. was identified in 53.8% of the samples collected by an electro-ejaculator and was not detected in ejaculates collected by an artificial vagina. The mean semen bacterial load detected during the breeding season was significantly (P<0.01) higher than that collected during the non-breeding season. No fungi were isolated from semen samples collected in the non-breeding season. The difference between the mean semen bacterial loads in the first and the second ejaculate was highly significant (P<0.01). The preputial wash significantly (P<0.01) reduced the bacterial load. This study revealed that the microbial contamination of dromedaries' semen is found in different intensities during different management procedures of semen collection.