Epidemiology and Scenario Simulations of the Middle East Respiratory Syndrome Corona Virus (MERS-CoV) Disease Spread and Control for Dromedary Camels in United Arab Emirates (UAE)

Middle East Respiratory Syndrome (MERS-CoV) is a coronavirus-caused viral respiratory infection initially detected in Saudi Arabia in 2012. In UAE, high seroprevalence (97.1) of MERS-CoV in camels was reported in several Emirate of Abu Dhabi studies, including camels in zoos, public escorts, and slaughterhouses. The objectives of this research include simulation of MERS-CoV spread using a customized animal disease spread model (i.e., customized stochastic model for the UAE; analyzing the MERS-CoV spread and prevalence based on camels age groups and identifying the optimum control MERS-CoV strategy. This study found that controlling animal mobility is the best management technique for minimizing epidemic length and the number of affected farms. This study also found that disease dissemination differs amongst camels of three ages: camel kids under the age of one, young camels aged one to four, and adult camels aged four and up; because of their immunological state, kids, as well as adults, had greater infection rates. To save immunization costs, it is advised that certain age groups be targeted and that intense ad hoc unexpected vaccinations be avoided. According to the study, choosing the best technique must consider both efficacy and cost.

Zoonotic diseases transmitted from the camels

Background

Zoonotic diseases, infections transmitted naturally from animals to humans, pose a significant public health challenge worldwide. After MERS-CoV was discovered, interest in camels was raised as potential intermediate hosts for zoonotic viruses. Most published review studies pay little attention to case reports or zoonotic epidemics where there is epidemiological proof of transmission from camels to humans. Accordingly, any pathogen found in camels known to cause zoonotic disease in other animals or humans is reported.

Methods

Here, zoonotic diseases linked to camels are reviewed in the literature, focusing on those with epidemiological or molecular evidence of spreading from camels to humans. This review examines the risks posed by camel diseases to human health, emphasizing the need for knowledge and awareness in mitigating these risks.

Results

A search of the literature revealed that eight (36.4%) of the 22 investigations that offered convincing evidence of camel-to-human transmission involved MERS, five (22.7%) Brucellosis, four (18.2%) plague caused by Yersinia pestis, three (13.6%) camelpox, one (4.5%) hepatitis E, and one (4.5%) anthrax. The reporting of these zoonotic diseases has been steadily increasing, with the most recent period, from 2010 to the present, accounting for 59% of the reports. Additionally, camels have been associated with several other zoonotic diseases, including toxoplasmosis, Rift Valley fever, TB, Crimean-Congo hemorrhagic fever, and Q fever, despite having no evidence of a transmission event. Transmission of human zoonotic diseases primarily occurs through camel milk, meat, and direct or indirect contact with camels. The above-mentioned diseases were discussed to determine risks to human health.

Conclusion

MERS, Brucellosis, plague caused by Y. pestis, camelpox, hepatitis E, and anthrax are the main zoonotic diseases associated with human disease events or outbreaks. Transmission to humans primarily occurs through camel milk, meat, and direct contact with camels. There is a need for comprehensive surveillance, preventive measures, and public health interventions based on a one-health approach to mitigate the risks of zoonotic infections linked to camels.

The evaluation of five serological assays in determining seroconversion to peste des petits ruminants virus in typical and atypical hosts

Peste des petits ruminants (PPR) is an infectious viral disease, primarily of small ruminants such as sheep and goats, but is also known to infect a wide range of wild and domestic Artiodactyls including African buffalo, gazelle, saiga and camels. The livestock-wildlife interface, where free-ranging animals can interact with captive flocks, is the subject of scrutiny as its role in the maintenance and spread of PPR virus (PPRV) is poorly understood. As seroconversion to PPRV indicates previous infection and/or vaccination, the availability of validated serological tools for use in both typical (sheep and goat) and atypical species is essential to support future disease surveillance and control strategies. The virus neutralisation test (VNT) and enzyme-linked immunosorbent assay (ELISA) have been validated using sera from typical host species. Still, the performance of these assays in detecting antibodies from atypical species remains unclear. We examined a large panel of sera (n = 793) from a range of species from multiple countries (sourced 2015-2022) using three tests: VNT, ID VET N-ELISA and AU-PANVAC H-ELISA. A sub-panel (n = 30) was also distributed to two laboratories and tested using the luciferase immunoprecipitation system (LIPS) and a pseudotyped virus neutralisation assay (PVNA). We demonstrate a 75.0-88.0% agreement of positive results for detecting PPRV antibodies in sera from typical species between the VNT and commercial ELISAs, however this decreased to 44.4-62.3% in sera from atypical species, with an inter-species variation. The LIPS and PVNA strongly correlate with the VNT and ELISAs for typical species but vary when testing sera from atypical species.

Isolation and genetic characterization of MERS-CoV from dromedary camels in the United Arab Emirates

Background

The study of coronaviruses has grown significantly in recent years.Middle East respiratory syndrome coronavirus (MERS-CoV) replicates in various cell types, and quick development has been made of assays for its growth and quantification. However, only a few viral isolates are now available for investigation with full characterization. The current study aimed to isolate MERS-CoV from nasal swabs of dromedary camels and molecularly analyze the virus in order to detect strain-specific mutations and ascertain lineage classification.

Methods

We isolated the virus in Vero cells and adapted it for in vitro cultivation. The isolates were subjected to complete genome sequencing using next-generation sequencing followed by phylogenetic, mutation, and recombination analysis of the sequences.

Results

A total of five viral isolates were obtained in Vero cells and adapted to in vitro cultures. Phylogenetic analysis classified all the isolates within clade B3. Four isolates clustered close to the MERS-CoV isolate camel/KFU-HKU-I/2017 (GenBank ID: MN758606.1) with nucleotide identity 99.90-99.91%. The later isolate clustered close to the MERS-CoV isolate Al-Hasa-SA2407/2016 (GenBank ID: MN654975.1) with a sequence identity of 99.86%. Furthermore, the isolates contained several amino acids substitutions in ORF1a (32), ORF1ab (25), S (2), ORF3 (4), ORF4b (4), M (3), ORF8b (1), and the N protein (1). The analysis further identified a recombination event in one of the reported sequences (OQ423284/MERS-CoV/dromedary/UAE-Al Ain/13/2016).

Conclusion

Data presented in this study indicated the need for continuous identification and characterization of MERS-CoV to monitor virus circulation in the region, which is necessary to develop effective control measures. The mutations described in this investigation might not accurately represent the virus's natural evolution as artificial mutations may develop during cell culture passage. The isolated MERS-CoV strains would be helpful in new live attenuated vaccine development and efficacy studies.

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.

Pathology and Molecular Epidemiology of Fowl Adenovirus Serotype 4 Outbreaks in Broiler Chicken in Abu Dhabi Emirate, UAE

BACKGROUND

Fowl adenovirus serotype 4 (FAdV-4), causing inclusion body hepatitis (IBH) and hydropericardium hepatitis syndrome (HPS), is responsible for the significant economic losses in poultry industry worldwide. This study describes FAdV disease and molecular characteristics of the virus as the first report in UAE.

METHODOLOGY

Clinical, necropsy, histopathology, qPCR and phylogenetic analysis of hexon gene were used to diagnose and characterize the virus.

RESULTS

The age of the infected broiler chicken was 2-4 weeks. The morbidity and mortality rates ranged between 50 and 100% and 44 and 100%, respectively. Clinically, sudden onset, diarrhea, anemia and general weakness were recorded. At necropsy, acute necrotic hepatitis, with swollen, yellowish discoloration, enlarged and friable liver; hydropericarditis with hydropericardium effusions; and enlarged mottled spleen were observed. Histopathology examination revealed degeneration and necrosis, lymphocytic infiltration and inclusion bodies. The qPCR analysis detected the virus in all samples tested. Hexon gene sequence analysis identified FAdV serotype 4, species C as the major cause of FAdV infections in UAE in 2020, and this strain was closely related to FAdV-4 circulating in Saudi Arabia, Pakistan, Nepal and China.

CONCLUSION

The serotype 4, species C, was the common FAdV strain causing IBH and HPS episodes in the region. This result may help design effective vaccination programs that rely on field serotypes.

A study on transmission of Peste des petits ruminants virus between dromedary camels and small ruminants

INTRODUCTION

In recent years Peste des petits ruminants (PPR) disease caused several epidemics in a wide range of susceptible hosts. The ability of the peste des petits ruminants virus (PPRV) to cross the species barrier necessitates further research, particularly on disease circulation and cross-species transmission between typical and atypical hosts to guide and facilitate the eradication program anticipated by the Food and Agriculture Organization (FAO) and the World Organization for Animal Health (OIE) in 2030. The aim of this study is to explore the role of dromedary camels as transmitters for PPR.

METHODOLOGY

Four experiments were carried out on clinically healthy seronegative camels, sheep and goats. In experiment I, the animals were inoculated with a PPR- positive suspension of camel pneumonic lung homogenate. In the other three experiments either sheep and goats were inoculated and after three days were housed with camels or vice versa.

RESULTS

Marked clinical signs suggestive of PPR were seen in sheep and goats while camels showed mild infection. Severe clinical signs of PPR were seen in sheep and goats when kept with inoculated camels. Postmortem examination revealed PPR lesions in all inoculated animals including camels.

CONCLUSIONS

This study showed that dromedary camels infected with PPRV can transmit the disease to sheep and goats, even when they developed mild clinical signs.

Epidemiology and laboratory diagnosis of very virulent infectious bursal disease virus in vaccinated chickens in Khartoum, Sudan

BACKGROUND

Infectious Bursal Disease (IBD, Gumboro disease) has become more severe than in early outbreaks in the 1980s. The present research aims to study the epidemiology of IBD in Khartoum state and compare some commonly used laboratory techniques for diagnosis.

METHOD

We collected epidemiological data from 30 farms that showed signs suggestive of IBD, estimated the morbidity and mortality rates, and interviewed the owners about the type and the doses of the used vaccines. We collected bursas of Fabricius for virus assays and histopathology. Samples positive in the agar gel immunodiffusion (AGID) test were inoculated onto chicken embryo fibroblast cell culture and embryonated chicken eggs. Twenty-two-day-old chicks were infected experimentally with three selected isolates, and morbidity and mortality rates were compared.

RESULTS

The results showed that 70% of outbreaks occurred between 6 and 8 weeks of age, and the mean mortality rate was 51%. Epidemiologic, clinical, gross, and histopathological findings were characteristic of the severe disease caused by the very virulent IBDvirus (vvIBDV). The farms that used intermediate or the intermediate plus vaccines had lowered mortality compared with the farms that used intermediate vaccines. The AGID was found more sensitive than the counter-immuno-electrophoresis (CIEP) since it detected 83.4% of the IBDV antigen in the samples while the CIEP detected 66.7% of the samples. The reverse transcriptase polymerase chain reaction (RT-PCR) was found to be rapid, specific, and was more sensitive detecting 100% of the tested samples. Virus isolation in embryonated eggs and cell culture was not successful.

CONCLUSION

A vvIBDV is responsible for the recent outbreaks of the disease in Sudan, resulting in a mean high mortality rate of 51%, even in vaccinated flocks. The RT-PCR and AGID are the best methods for laboratory confirmation.

Molecular Investigation on Tick-Borne Hemoparasites and Coxiella burnetii in Dromedary Camels (Camelusdromedarius) in Al Dhafra Region of Abu Dhabi, UAE

Camels represent an important resource for inhabitants of the most arid regions of the world and their survival is mainly related to environment conditions including the risk of parasitic diseases, which may represent a significant cause of losses in livestock production of these areas. Camels may be parasitized by several hematophagous arthropods, which can be vectors of several diseases including zoonosis. This study aimed to investigate in dromedary camels and their ticks the importance of tick-borne hemoparasites that might be responsible for a recent and obscure morbidity of camels in Al Dhafra region of Abu Dhabi, UAE. Blood samples and ticks from 93 naturally infected camels belonging to 36 herds, affected by variable acute clinical syndromes lasting from 3 to 5 days, were analyzed through molecular techniques for specific DNA presence of different blood pathogens: Anaplasmamarginale/Anaplasmaovis, Anaplasma phagocytophilum, Coxiella burnetii,Babesia spp., and Theileria spp. DNA. All the 72 ticks collected belonged to the Hyalomma dromedarii species and were negative for blood pathogens. n = 15 camels (16.1%) were found positive to the following tick-borne hemoparasites: A. phagocytophilum 11 (11.8%), Coxiella burnetii 3 (3.2%), and Babesia/Theileria spp. 2 (2.1%). One singular camel showed coinfection of C. burnetii and A. phagocytophiulm. Genetic profile of C. burnetii showed a high phylogenetic relatedness to European, Asian and African C. burnetii strains. This is the first laboratory investigation on tick-borne pathogens in camels in UAE, and the first report of A. phagocytophilum and C. burnetii. Moreover, since the detected pathogens are recognized pathogens for humans, this study highlights the zoonotic risk for humans working in camel husbandry.

Pathology, bacteriology and molecular studies on caseous lymphadenitis in Camelus dromedarius in the Emirate of Abu Dhabi, UAE, 2015-2020

Caseous lymphadenitis (CLA) or pseudotuberculosis is a chronic zoonotic bacterial disease caused by Corynebacterium pseudotuberculosis, which affects livestock and humans. This study aimed to describe the pathology, bacteriology and confirm the identity of the pathogen by 16S rRNA gene sequencing in Camelus dromedarius. A total of 12 camels with suspected CLA in three regions of Abu Dhabi Emirate (Abu Dhabi, Al Ain and Al Dhafra), United Arab Emirate (UAE) were subjected to clinical and postmortem examinations from January 2015 to December 2020. Clinically, camels were emaciated and showed the presence of external caseous abscesses suggestive of CLA. Postmortem examination showed multiple abscesses of variable sizes with caseous material encapsulated by fibrous tissue in the liver, lungs, muscle, and lymph nodes. Following clinical and postmortem examination, blood, pus and different tissue samples were collected for subsequent analysis. Histopathological examination of all organs stained with Hematoxylin and Eosin (H&E) indicated a central caseo-necrotic core that was admixed with bacterial colonies and infiltration of chronic inflammatory cells, surrounded by a pyogenic membrane, and an outer fibrous connective tissue capsule. Bacterial culture identified the isolates of Corynebacterium pseudotuberculosis biotype ovis strain, and these isolates were shown to be sensitive to all antibiotics tested (penicillin, ampicillin, Co-trimoxazole, enrofloxacin and tetracycline). Moreover, the identity of the isolates was confirmed by partial sequencing of the 16S rRNA gene which showed a 100% identity to Corynebacterium pseudotuberculosis. Phylogenetic analysis based on 16S rRNA gene sequence clearly differentiates Corynebacterium pseudotuberculosis from other species of Corynebacterium. Briefly, this study provided the basic information for infection of Corynebacterium pseudotuberculosis in Camels and will help in controlling of this pathogen in the region.

Gangrenous mastitis in dromedary camels in UAE caused by Streptococcus agalactiae

BACKGROUND

Mastitis is a disease of economic concern that affects dairy industry worldwide. This study aimed to investigate and identify possible etiologies encountered in an episode of acute gangrenous mastitis in lactating she-camels in Al Dhafra region, Abu Dhabi Emirate, United Arab Emirates (UAE). Beside the routine clinical examination, conventional bacteriological methods were used to isolate and identify possible aerobic/anaerobic bacterial or fungal pathogens from cultured milk samples collected from the mastitic she-camels. Moreover, quantitative real-time polymerase chain reaction (qPCR) was used for the detection of Mycoplasma agalactiae and Mycoplasma bovis strains, and the 16S rRNA gene was sequenced to confirm the isolation. The isolates were also tested for their susceptibility to antimicrobials.

RESULTS

Acute gangrenous mastitis is reported in the dromedary camel herd with about 80% morbidity rate among lactating she-camels exhibited acute, painful hard swelling of affected teat, quarter or entire udder. About 41.7% of the infected animals were stamped out for culling due to complete or partial amputation of udder quarters. Streptococcus agalactiae was the sole isolated organism (6 isolates). The antimicrobial susceptibility testing revealed that, the Streptococcus agalactiae isolates were sensitive to both penicillin and ampicillin. Comparison of the 16S rRNA gene sequencing results by BLASTN confirmed the presence of Streptococcus agalactiae with high confidence (100% identity). Phylogenetic analysis indicated clustering of one isolate (CMAUAE accession number; MN267805.1) with Streptococcus agalactiae that infects multi-hosts including humans, while strains (CMBUAE to CMFUAE with accession numbers; MN267806.1 to MN267810.1 respectively) clustered with Streptococcus agalactiae that infects humans. No Mycoplasma spp was detected by qPCR analysis.

CONCLUSIONS

In the present study, the Streptococcus agalactiae was found to be the main cause of acute gangrenous mastitis in dromedary camels in UAE. More research should be done to investigate other possible causes of clinical or subclinical mastitis in dromedary camels in UAE.

Preliminary Comparative Assessment of Brucellergene Skin Test for Diagnosis of Brucellosis in Dromedary Camels (Camelus dromedarius)

This study was conducted to evaluate the use of Brucellergene skin test (BST) for the diagnosis of Brucellosis in camels (Camelus dromedarius) in comparison with Rose Bengal test (RBT) and competitive enzyme-linked immunosorbent assay (c-ELISA). A total of 68 apparently healthy adult dromedary camels of either gender from three different geographical locations of Abu Dhabi Emirate, United Arab Emirates (UAE), were included in the study. The skin test was applied on two shaved areas at the middle of the neck: one for the test and the other area was injected with normal saline as a control. Reading was done 72 h postinjection. Results were subjected to Bayesian analysis to assess the test performances in camels. The model estimated the following sensitivity and specificity median values: BST: Se = 70.72%, Sp = 98.82%; RBT: Se = 93.27%, Sp = 97.79%; and c-ELISA: Se = 94.78%, Sp = 98.48%. As the BST investigated in this study proved to be a highly specific test, we propose using it as a confirmatory test in camels particularly when the serological tests give doubtful results on individual animals.

Field investigation and phylogenetic characterization of orf virus (ORFV) circulating in small ruminants and Pseudocowpoxvirus (PCPV) in dromedary camels of eastern Sudan

In this study, livestock herders in eastern Sudan were interviewed through structured questionnaire involved 14046 animals in 151 herds (87 camel herds, 51 sheep and 13 goats) from June to September of 2016 in Showak area of Gadarif State to get some epidemiological information on contagious ecthyma (CE) infection. 102 suspected cases of CE were investigated (38 sheep, 22 goats and 42 camels) by a second questionnaire focusing on age and sex of affected animals beside number and localization of the lesions. Representative tissue samples of scab lesion scrapings were collected from a total of 36 suspected sheep, goats and camels for DNA extraction to identify PPV by quantitative real-time PCR and gel-based PCR, then a PCR protocol was used to obtain DNA fragment of B2L gene from six DNAs (2 from each animal species) for sequencing. Phylogenetic tree based on nucleotide sequences was constructed and all data were analyzed statistically. Obtained result has shown morbidity rate of 23.8% and a case fatality rate of 4.7 % in overall investigated animals resulting in a significant economic loss. Within individual herd, the morbidity rate varied from 5.6 to 42.8%, while the case fatality rate ranged between 0 and 33.3%. Camels accounted for the highest case fatality rate with 6.5% compared to sheep and goats which their rates were 2.8% and 1.3%, respectively. 93% of the affected animals were young less than one-year-old. The prevalence of CE was high in the rainy season compared to winter and summer. Out of 36 scab materials collected from sheep, goats, and camels, 24 gave positive specific amplification in real-time PCR and 21 in the gel-based PCR. DNA sequencing confirmed the PCR results. All sequences had a high G + C content of 62.6-63.9%. A BLAST search also revealed that the studied sheep PPV (SPPV) isolates shared 99.08% nucleotide sequence intragroup identity, 96.88-97.27% identity with the goat PPV (GPPV) isolates and together they belong to the Orf virus (ORFV) species, while the camel PPV (CPPV) isolates are close to the Pseudocowpoxvirus (PCPV) species of the PPV genus and share 92.51-93.62 % identity with the GPPV isolates. In conclusion the present study demonstrated that the gross lesion produced by PPV in sheep, goats and camels is generally similar, yet the PPVs circulating in eastern Sudan in camels (PCPV) are genetically distinct from those affecting sheep and goats (ORFV). Contagious ecthyma in eastern Sudan causes significant morbidities and mortalities and control measures, guided by the results of this investigation ought to be implemented.

Salmonella enterica and Theileria co-infection in dromedary camels (Camelus dromedarius) in UAE

BACKGROUND

Despite a steady increase in camel husbandry worldwide, pathology of camel diseases is still relatively under-investigated. Clinical hematuria is generally indicative of either acute or chronic urogenital inflammations, traumatic calculous injuries, cancers, corrosive poisonings. Infectious agents are not typically implicated in urinary tract infection of camels.

AIM

This study aims to explore possible causes in camels clinically suffered from acute febrile disease with severe hematuria.

METHODS

To achieve aims of the study culturing of urine samples, microscopic examination for detection of blood parasites, phenotypic and genotypic characterization for the identification of isolated bacteria were followed.

RESULTS

Conventional bacteriology enabled identification of Salmonella enterica subsp. enterica serovar typhimurium which further genotyped by 16S rRNA gene sequencing. Microscopic examination of Giemsa stained blood smears from both infected dromedary camels revealed the presence of pleomorphic Theileria piroplasms. The results suggest that the clinical symptoms were as coinfection induced by salmonellosis and theileriosis.

CONCLUSION

Given these remarkable findings, further research should aim to better characterize the opportunistic pathogens associated with camel theileriosis, as well as to determine other possible infectious agents of the camel urinary tract.

Diversity of Middle East respiratory syndrome coronaviruses in 109 dromedary camels based on full-genome sequencing, Abu Dhabi, United Arab Emirates

Middle East respiratory syndrome coronavirus (MERS-CoV) was identified on the Arabian Peninsula in 2012 and is still causing cases and outbreaks in the Middle East. When MERS-CoV was first identified, the closest related virus was in bats; however, it has since been recognized that dromedary camels serve as a virus reservoir and potential source for human infections. A total of 376 camels were screened for MERS-Cov at a live animal market in the Eastern Region of the Emirate of Abu Dhabi, UAE. In all, 109 MERS-CoV-positive camels were detected in week 1, and a subset of positive camels were sampled again weeks 3 through 6. A total of 126 full and 3 nearly full genomes were obtained from 139 samples. Spike gene sequences were obtained from 5 of the 10 remaining samples. The camel MERS-CoV genomes from this study represent 3 known and 2 potentially new lineages within clade B. Within lineages, diversity of camel and human MERS-CoV sequences are intermixed. We identified sequences from market camels nearly identical to the previously reported 2015 German case who visited the market during his incubation period. We described 10 recombination events in the camel samples. The most frequent recombination breakpoint was the junctions between ORF1b and S. Evidence suggests MERS-CoV infection in humans results from continued introductions of distinct MERS-CoV lineages from camels. This hypothesis is supported by the camel MERS-CoV genomes sequenced in this study. Our study expands the known repertoire of camel MERS-CoVs circulating on the Arabian Peninsula.

Peste des petits ruminants infection in domestic ruminants in Sudan

The existence of peste des petits ruminants (PPR) in domestic ruminants and camels in Sudan during 2008-2012 was investigated. Lung tissues and serum samples were randomly collected from sheep, goats, cattle, and camels at different areas of Sudan. A total of 12,384 serum samples were collected from clinically healthy 7413 sheep, 1988 camels, 1501 cattle, 1459 goats, and 23 gazelles at different areas in the Sudan. They were examined for PPR antibodies using competitive ELISA (cELISA). The overall detected seroprevalence of PPR in tested sera was 49.4%; seroprevalence values within species were 67.1, 48.2, 25.8, 2.1, and 21.7% in sheep, goat, cattle, camels, and gazelles, respectively. The highest seroprevalence (68.1%) was observed in sera collected from Darfur states, then the central states (54.3%). A total of 1276 lung tissue samples (623 sheep, 324 cattle, 220 camels, and 109 goats) were collected. The majority of lung samples were collected from clinically healthy animals that showed lesions on PM in slaughterhouses (95%) and during PPR outbreaks; samples were tested for PPR antigen using immunocapture ELISA (IcELISA). PPR antigen was detected in 233 out of the 1276 tested samples (18.3%). Positive results were observed in samples collected from clinically healthy and diseased animals. The observed prevalence values in each species were 33.6, 21.1, 15.4, and 12.3% in camel, goat, sheep, and cattle, respectively. PPR antigen was detected in samples from different areas; however, the highest prevalence (63.9%) was found in samples collected from the eastern states, then Khartoum state (28%). Trials for virus isolation were done in different cell cultures. Out of 30 IcELISA-positive samples inoculated in primary bovine and ovine kidney cells, Vero cells, the PPR virus was successfully isolated from 15 (eight sheep, five camels, and two goats) samples in the three cell culture types. Using RT-PCR, PPRV nucleic acid was detected in all 25 IcELISA-positive tested samples.

Identification of diverse viruses in upper respiratory samples in dromedary camels from United Arab Emirates

Camels are known carriers for many viral pathogens, including Middle East respiratory syndrome coronavirus (MERS-CoV). It is likely that there are additional, as yet unidentified viruses in camels with the potential to cause disease in humans. In this study, we performed metagenomic sequencing analysis on nasopharyngeal swab samples from 108 MERS-CoV-positive dromedary camels from a live animal market in Abu Dhabi, United Arab Emirates. We obtained a total of 846.72 million high-quality reads from these nasopharyngeal swab samples, of which 2.88 million (0.34%) were related to viral sequences while 512.63 million (60.5%) and 50.87 million (6%) matched bacterial and eukaryotic sequences, respectively. Among the viral reads, sequences related to mammalian viruses from 13 genera in 10 viral families were identified, including Coronaviridae, Nairoviridae, Paramyxoviridae, Parvoviridae, Polyomaviridae, Papillomaviridae, Astroviridae, Picornaviridae, Poxviridae, and Genomoviridae. Some viral sequences belong to known camel or human viruses and others are from potentially novel camel viruses with only limited sequence similarity to virus sequences in GenBank. A total of five potentially novel virus species or strains were identified. Co-infection of at least two recently identified camel coronaviruses was detected in 92.6% of the camels in the study. This study provides a comprehensive survey of viruses in the virome of upper respiratory samples in camels that have extensive contact with the human population.

Investigation on papillomavirus infection in dromedary camels in Al-Ahsa, Saudi Arabia

We investigated two outbreaks of papillomatosis between 2013 and 2015 in Al Ahsa region of eastern Saudi Arabia involving fourteen dromedary camels. The disease affected both young and adult animals and occurred in coincidence with demodectic mange infestation. Diagnosis was made based on gross and histopathological characteristics of the wart lesion and was confirmed by PCR. Rolling circle amplification followed by degenerate primer PCR and sequencing of the amplicons revealed the presence of both Camelus dromedarius papillomavirus types 1 and 2, previously identified in infected dromedaries in Sudan.

An Epidemiological Study of Sheep and Goat pox Outbreaks in the Sudan

Sheep and goat pox Outbreaks occurred in different geographic areas of Sudan and most strikingly, were highly species specific. Two outbreaks in Gedarif State in June. 2013 affected no goats and outbreak in Khartoum state in March. 2015 affected no sheep despite communal herding; affected goats were vaccinated with 0240 strain. Clinically, the disease was characterized by fever, depression and eruption of generalized pox lesions. Mortality rate ranged between 5.2 and 6.7% with a mean of 6.1%. Isolation of viruses succeed on Lamb testes cell culture at passage four, the diseases were diagnosed using virus neutralisation test and polymerase chain reaction. Sheeppox and goatpox isolates grew well in lamb testes and Vero cells. In MDBK however, both viruses induced slight CPE that reached 60% in 9 days. On the other hand, both isolates induced no CPE in chick embryo fibroblast cells. Virus isolation attempts failed on chorioallantoic membrane of embryonated chicken eggs.

Development and evaluation of a live attenuated camelpox vaccine from a local field isolate of the virus

A strain of camelpox virus (CMLV) isolated in the Sudan was attenuated by serial passage in Vero cell monolayers for use as a future vaccine strain. The safety and potency of passage 115 virus (designated Sudan CMLV/115) was tested. Camels inoculated with CMLV/115 showed no clinical disease or skin lesions, developed low-level antibodies and cell-mediated immune response and resisted challenge with virulent wild-type CMLV. Field testing of the candidate vaccine showed that the developed vaccine induces immune response and is safe for young and pregnant camels.

Characterization of the complete genomes of Camelus dromedarius papillomavirus types 1 and 2

Camel papillomatosis has been described previously, but the genome of the suspected papillomavirus (PV) has not been identified. An outbreak of papillomatosis occurred in a dromedary farm of 55 animals in Sudan during August 2009. The disease was only present in young animals aged about 3-7 months, of which 44 % (11/25) were affected with lesions, mainly on the lips and lower jaw. This study reports for the first time the complete genomes of Camelus dromedarius papillomavirus types 1 (CdPV1) and 2 (CdPV2), isolated from a cauliflower-like nodule and a round oval raised nodule, respectively. Pairwise comparisons of their L1 nucleotide sequences revealed 69.2 % identity, and phylogenetic analyses suggested that these two PV types are grouped within the genus Deltapapillomavirus. Both viruses were isolated from fibropapillomas, although no putative E5 proteins homologous to that of bovine papillomavirus type 1 were identified. The genetic information will be useful for evolutionary studies of the family Papillomaviridae, as well as for the development of diagnostic methods for surveillance of the disease in dromedaries.

Analysis and effect of water sources used as diluents on Newcastle disease vaccine efficacy in chickens in the Sudan

Samples of artesian well, shallow well, surface water, tap water, and bottled water were collected from different areas in Khartoum; these were chemically analyzed and used as diluents to vaccinate chicks against Newcastle disease. Immune response in vaccinated chicks, as measured by the hemagglutination inhibition test, was significantly better in birds which received the vaccine diluted in bottled water followed by those vaccinated using tap water. It appears that water with low turbidity and total dissolved solids were the best water for vaccine dilution. The order of preference of water source, according to this study was bottled water, tap water, shallow well water, artesian well water, and finally surface water.

Respiratory syncytial virus infection of camels (Camelus dromedaries)

This study aimed to investigate the occurrence of respiratory syncytial virus (RSV) infections in camels in Sudan. A total of 272 camel lung specimens showing pneumonia were collected from slaughter houses at four different areas in Sudan, additionally 8 specimens were collected from outbreaks of respiratory infection in camels. Using sandwich ELISA kits for RSV antigen detection 4 out of 280 tested lungs (1.4%) were positive, all were from Central Sudan (Tambool slaughter house). FAT was used to confirm the ELISA positives. Polymerase chain reaction RT/PCR was applied for the detection of RSV genome in camel lungs; 1 out of 4 ELISA positives was positive by RT/PCR. Using indirect ELISA kits 135 out of 495 (27.3%) camel sera showed antibodies to RSV, highest prevalence was observed in Western (33.5%) then Central (31.6%) and Eastern Sudan (23.5%). Based on the manufacturer specified calculations for OD readings, most of positive sera (90/135) were low reactive (1+). This is the first report for the detection of RSV antigen, genome and antibody in camels in Sudan.

Respiratory infection of camels associated with parainfluenza virus 3 in Sudan

This study was undertaken to investigate the role of parainfluenza virus 3 (PIV3) in respiratory infection of camels. A total of 273 lung specimens from camels with pneumonia lesions were collected from slaughterhouses in four different areas of Sudan. In addition, eight specimens were collected from outbreaks of respiratory infection in camels. Using antigen detection sandwich ELISA kits, six out of the 281 specimens tested were positive for the PIV3 antigen (2.1%); the highest prevalence was noted in Eastern Sudan (4.2%), then in Central and Northern Sudan (1.4%). The direct immunofluorescent test (FAT) was used to confirm the positive reactions for PIV3 by ELISA. The polymerase chain reaction (RT-PCR) was applied for the detection of the PIV3 genome in lungs of camels; two out of four samples which were positive by the PIV3 ELISA were also positive by RT-PCR. Virus isolation was attempted for PIV3 in MDBK cells; four specimens yielded cytopathic virus when inoculated onto the cell culture. The cytopathic effect (CPE) consisted of cell rounding, multinucleated cells, sloughing and elongation of cells, and some syncytia were observed on the 3rd to 7th day post-inoculation. Using commercially available indirect ELISA kits for antibodies to PIV3, 495 camel sera were tested, and the seroprevalence detected was 82.2%. The highest seroprevalence was observed in Central (92.6%), then in Eastern (92.2%) and Central to South Sudan (82.5%); the lowest prevalence was found in Northern Sudan (64.8%).

Detection of camel pox and vaccinia viruses by polymerase chain reaction

PCR following two methods of DNA extraction was used to confirm the growth of camel pox virus (CPV) and vaccinia virus in cell culture and chorioallantoic membrane. Results were compared with the commonly used neutralization test. The first method of DNA extraction was accomplished by using viral DNA in tissue culture supernatant and Chorioallantoic membrane, which was released by initial heating for 15 min at 99 degrees C followed by ordinary PCR. In the second method DNA was extracted by using DNA Isolation Kit from tissue culture supernatant and used as a template. Rapid identification and differentiation of CPV and Vaccinia virus were achieved by PCR and this assay proved to be fast and feasible, and can be an alternative to orthodox serological methods.

Natural exposure of Dromedary camels in Sudan to infectious bovine rhinotracheitis virus (bovine herpes virus-1)

The occurrence of bovine herpes virus-1 (BHV-1) in camels was studied. A total of 186 pneumonic camel lungs were collected from slaughter houses at four different areas in Sudan during 2000-2006. Using sandwich ELISA 1.6% of 186 tested lungs were found positive for BHV-1 antigen, all were from Tambool at Central Sudan. Direct fluorescent antibody test (FAT) was used to confirm the BHV-1 ELISA positives, all ELISA positives were also positive. PCR was used to detect BHV-1 genome with three positive results. BHV-1 was isolated from two camel lungs in MDBK cells. Isolates were identified using ELISA and FAT. Indirect ELISA was used to detect antibodies to BHV-1 in 260 camel sera; 76.9% were found positive. Highest prevalence was observed in sera from Kordofan (84%) then Blue Nile (80%) and Tambool (76.3%). This is the first report for the detection of BHV-1 antigen, genome using PCR, isolation in cell culture and antibodies in camels in Sudan.

Observations on the use of Komarov strain of Newcastle disease vaccine in the Sudan

Broilers at 18 days old were vaccinated with a single dose of the K strain of Newcastle disease vaccine administered by different routes. The serological results obtained by haemagglutination inhibition at weekly intervals post-vaccination showed that birds vaccinated intranasally (i/n) or intramuscularly (i/m) had antibody titres higher than those vaccinated by the oral method. Furthermore, when challenged 3 weeks after vaccination, those broilers vaccinated i/n or i/m had 75% and 70% resistance respectively, while those vaccinated by the oral or spray methods failed to withstand the challenge.

Lumpy skin disease: observations on the recent outbreaks of the disease in the Sudan

Outbreaks of lumpy skin disease in imported Friesian and indigenous cattle which occurred in the Khartoum State during the period of 1989-1991, are described. The disease was diagnosed from clinical findings, isolation and identification of the virus and from electron microscopy. Clinical findings included pyrexia, nasal discharge, appearance of multiple skin nodules of varying sizes, oedema of legs and brisket and abortion. The disease in purebred Friesian cattle was severe with a morbidity rate of 37.9% and a mortality rate of 4.2% while it was rather mild in indigenous cattle.

Salmonella enteritidis infection in the Sudan

Twenty-one Salmonella enteritidis isolates were recovered from several poultry farms in three states in the Sudan over an eighteen-month period. The infection was disseminated from a distributing company which had imported infected fertilized eggs and parent stock. The Sudan S. enteritidis epidemic which devastated many poultry farms during 1990 was attributable and concurrent to that in Europe in particular and throughout the world in general.

Pathogenic properties of Newcastle disease virus isolates in the Sudan

Six Newcastle disease virus (NDV) isolates were obtained from disease outbreaks on different poultry farms in the Sudan between 1988 and 1991. The pathogenic properties of these isolates were studied in comparison to those of strain Herts 33/56. All the isolates were similar in that they killed chicken embryos quickly, in mean death time (MDT) and embryo lethal dose 50 per cent (ELD50), had higher intracerebral pathogenicity indices (ICPI), and produced viscerotropic lesions in the infected chickens. The field isolates had the characteristics of the velogenic viscerotopic strains of NDV. The pathogenesis of infection caused by one of the isolates was studied. The virus was first detected in different organs and in oral and cloacal swabs on the third day after infection.