Bovine herpesvirus-1 (BHV-1), bovine leukemia virus (BLV) and bovine viral diarrhea virus (BVDV) infections in Algerian dromedary camels (Camelus dromaderius)

The one-humped camel: The animal of future, potential alternative red meat, technological suitability and future perspectives

The 2020 world population data sheet indicates that world population is projected to increase from 7.8 billion in 2020 to 9.9 billion by 2050 (Increase of more than 25%). Due to the expected growth in human population, the demand for meats that could improve health status and provide therapeutic benefits is also projected to rise. The dromedary also known as the Arabian camel, or one-humped camel ( Camelus dromedarius), a pseudo ruminant adapted to arid climates, has physiological, biological and metabolic characteristics which give it a legendary reputation for surviving in the extreme conditions of desert environments considered restrictive for other ruminants. Camel meat is an ethnic food consumed across the arid regions of Middle East, North-East Africa, Australia and China. For these medicinal and nutritional benefits, camel meat can be a great option for sustainable meat worldwide supply. A considerable amount of literature has been published on technological aspects and quality properties of beef, lamb and pork but the information available on the technological aspects of the meat of the one humped camel is very limited. Camels are usually raised in less developed countries and their meat is as nutritionally good as any other traditional meat source. Its quality also depends on the breed, sex, age, breeding conditions and type of muscle consumed. A compilation of existing literature related to new technological advances in packaging, shelf-life and quality of camel meat has not been reviewed to the best of our knowledge. Therefore, this review attempts to explore the nutritional composition, health benefits of camel meat, as well as various technological and processing interventions to improve its quality and consumer acceptance. This review will be helpful for camel sector and highlight the potential for global marketability of camel meat and to generate value added products.

Usefulness of Next-Generation Sequencing in Excluding Bovine Leukemia Virus as a Cause of Adult Camel Leukosis in Dromedaries

Adult camel leukosis is an emerging hematological and neoplastic disease in dromedaries. It has been hypothesized that bovine leukemia virus (BLV) or its genetic variants may be associated with adult camel leukosis. In this study, we used next-generation sequencing (NGS) to detect all possible viruses in five lung samples from five dromedaries with histopathological evidence of adult camel leukosis and four tissue samples from two control dromedaries. A total throughput of 114.7 Gb was achieved, with an average of 12.7 Gb/sample. For each sample, all the pair-end 151-bp reads were filtered to remove rRNA sequences, bacterial genomes and redundant sequences, resulting in 1-7 Gb clean reads, of which <3% matched to viruses. The largest portion of these viral sequences was composed of bacterial phages. About 100-300 reads in each sample matched "multiple sclerosis-associated retrovirus", but manual analysis showed that they were only repetitive sequences commonly present in mammalian genomes. All viral reads were also extracted for analysis, confirming that no BLV or its genetic variants or any other virus was detected in the nine tissue samples. NGS is not only useful for detecting microorganisms associated with infectious diseases, but also important for excluding an infective cause in scenarios where such a possibility is suspected.

Risk-associated factors associated with the bovine viral diarrhea virus in dromedary camels, sheep, and goats in abattoir surveillance and semi-closed herd system

Background and Aim:

Bovine viral diarrhea virus (BVDV) is one of the most important viral pathogens causing high economic losses in cattle of all ages. Despite the active vaccination campaigns against BVDV, many outbreaks are still detected in various populations of cattle worldwide. Other species of animals such as dromedary camels, sheep, and goats may harbor BVDV infection and cause variable clinical syndromes. Thus, they may act as a source of infection to the cattle population around them. However, little is still known about the roles of these animals in the viral transmission and sustainability of BVDV in the environment. This study aimed to explore if the dromedary camels, sheep, and goats may seroconvert against BVDV and to study some associated risk factors for BVDV in these species of animals.

Materials and Methods:

We tested 1012 serum samples from dromedary camels, 84 from goats, and 21 from sheep for BVDV antibodies using commercial enzyme-linked immunosorbent assay (ELISA) kits. Meanwhile, we selected 211 serum samples from dromedary camels to be tested for the BVDV antigen using the commercial ELISA kits.

Results:

Our results show that 49/1117 serum samples were positive for the BVDV antibodies in dromedary camels (46/1012), goats (3/84), and none of the tested sheep samples were positive. However, none of the collected serum samples tested positive for the BVDV antigen.

Conclusion:

Seroconversion of some dromedary camels, sheep, and goats to the BVDV with no history of vaccination against BVDV strongly suggests the potential roles of these species of animals in the virus transmission cycle. The main limitations of the current study are (1) the lack of samples from other species of animals that lived close by these animals, particularly cattle. (2) lack of follow-up samples from the same animal over a long period. We believe the long-term longitudinal study of BVDV in various species of animals, particularly dromedary camels, goats, and sheep, is one of our future research directions. This will provide more information about the dynamics of BVDV antibodies in these species of animals.

Preparation and field study of combined vaccine against Clostridium perfringens type A and bovine viral diarrhea virus in camels

Purpose

The key objective of this study was to formulate a local combined inactivated gel adjuvanted vaccine containing bovine viral diarrhea virus (BVDV)-1, BVDV-2 viruses and Clostridium perfringens type A toxoid. The study evaluated its ability to enhance protective active immune response in camels’ calves against these infectious pathogens under field conditions.

Materials and Methods

The local BVDV cytopathic strains and a local strain of toxigenic C. perfringens type A were used in vaccines formulation. Vaccines A and B were monovalent vaccines against C. perfringens and both strains of BVDVs, respectively. While the vaccine C was the combined vaccine used against the three agents. All vaccines were adjuvanted with Montanide gel. Sterility, safety, and potency tests were applied on the formulated vaccines. Virus neutralization and toxin anti-toxin neutralization tests were used to evaluate the immune responses.

Results

Both monovalent (vaccine A) and combined vaccines (vaccine C) showed a protective level (4.5 and 3 IU/mL, respectively) against C. perfringens from the 2nd-week post-vaccination. The titer declined to 3 and 2 IU/mL, respectively at the 5th-month post-vaccination. The titer against BVDV, the monovalent vaccine (vaccine B) reached the beak (1.95 IU/mL) at the 1st-month post-vaccination and lasted till 6th-month post-vaccination (0.92 and 0.94 IU/mL) for BVDV-1a and BVDV-2, respectively.

Conclusion

Vaccination of camels with the combined vaccine adjuvanted by Montanide gel containing C. perfringens type A toxoid and BVDV strains with 6-month intervals is recommended to protect camels safely and efficiently against such infections in the field.

BVDV, BHV-1 and BLV antibodies in dromedary camels of Turkey kept without and with ruminants

Camels are the only animals bred to sustain the tradition of wrestling in Turkey and are reared within a limited set of geographic areas. Farmers of such animals may also be engaged in ruminant breeding. The current research was aimed at documenting bovine viral diarrhoea virus (BVDV), bovine herpesvirus-1 (BHV-1), and bovine leukaemia virus (BLV) infections in sera collected from dromedary camels in four different geographical regions of Turkey during the years 2019-2021. All samples were tested for BVDV, BHV-1 and BLV antibodies as well as BVDV antigen by ELISA. Antibodies against BVDV were found in 16.8% of the camel sera tested. However, none of the camels sampled were positive in terms of BHV-1 and BLV antibodies as well as BVDV antigen. The prevalence was observed higher in the herds in which ruminants were raised in addition to camels (OR = 4.583, 95% CI, 1.298-16.182), (p = 0.018), while the prevalence was observed lower in the herds in which only camels were raised. This study showed that BVDV infection was more prevalent than BHV-1 and BLV infections in Turkish dromedary camels. Herewith, the camels, being a susceptible species to numerous viral ruminant diseases, may also serve as an important source of BVDV infection for other ruminant animals in the same flock.

Non-Bovine Species and the Risk to Effective Control of Bovine Viral Diarrhoea (BVD) in Cattle

Bovine viral diarrhoea virus (BVDV) is an economically important and highly prevalent virus of domestic cattle. Infections with BVDV may lead to both, reproductive and immunological effects that can result in widespread calf losses and increased susceptibility to diseases, such as mastitis and respiratory disease. While BVDV is generally considered to be host specific, it and other Pestivirus species, such as Border disease virus (BDV) in sheep, have been shown to be infecting species other than those from which they were originally isolated from. Recently BVDV was placed on the OIE’s list of notifiable disease and control and eradication programmes for BVDV have been developed throughout much of Europe, the United States, and the United Kingdom. While some countries, including Sweden and Ireland have successfully implemented eradication programmes, other countries such as New Zealand and Australia are still in the early stages of BVDV control. Despite effective control methods, incursions of BVDV into previously cleared herds still occur. While the cause of these incursions is often due to lapses in control methods, the ability of ruminant pestiviruses to infect species other than cattle poses the question as to whether non-bovine species could be impeding the success of BVDV eradication and control. As such, the aim of this review is to make mention of what is known about the cross-species transmission of BVDV, BDV and other pestiviruses between cattle and non-bovine ungulate species and draw conclusions as to the risk non-bovine species pose to the successful control and eradication of BVDV from cattle.

First serological evidence of BHV-1 virus in Algerian dromedary camels: Seroprevalence and associated risk factors

Infectious bovine rhinotracheitis (IBR), caused by bovine herpesvirus-1 (BHV-1), is a major livestock health concern in many countries of the world. The objectives of this cross-sectional study were (i) to estimate the seroprevalence of BHV-1 infection and (ii) to assess risk factors associated with this disease in dromedary camels in four districts of Algeria. Blood samples were taken from 865 camels from 84 randomly selected herds, and serum was analyzed for presence of antibodies against BHV-1 by indirect enzyme linked immunosorbent assay (ELISA). Logistic regression was used to determine associations between seroprevalence and potential risk factors (collected using a questionnaire). Antibodies against BHV-1 were detected in 3.7 % (32/865) of samples. Eighteen of 84 camel herds had at least one BHV-1 seropositive camel, giving a herd seroprevalence of 21.4 %. Based on univariate analysis, the introduction of purchased animals and contact with others animal herds appeared as major risk factors. By using multivariate analysis, the only important risk factor was introduction of new animals. This study provided, for the first time, evidence of BHV-1 infection in dromedary camels in Algeria; it also provided estimates of seroprevalence of this disease and suggests that camels may serve as a reservoir of BHV-1 for spread to other species.

Coxiella burnetii in Dromedary Camels (Camelus dromedarius): A Possible Threat for Humans and Livestock in North Africa and the Near and Middle East?

The "One Health" concept recognizes that human health is connected to animal health and to the ecosystems. Coxiella burnetii-induced human Q fever is one of the most widespread neglected zoonosis. The main animal reservoirs responsible for C. burnetii transmission to humans are domesticated ruminants, primarily goats, sheep, and cattle. Although studies are still too sparse to draw definitive conclusions, the most recent C. burnetii serosurvey studies conducted in herds and farms in Africa, North Africa, Arabian Peninsula, and Asia highlighted that seroprevalence was strikingly higher in dromedary camels (Camelus dromedarius) than in other ruminants. The C. burnetii seroprevalence in camel herds can reach more than 60% in Egypt, Saudi Arabia, and Sudan, and 70 to 80% in Algeria and Chad, respectively. The highest seroprevalence was in female camels with a previous history of abortion. Moreover, C. burnetii infection was reported in ticks of the Hyalomma dromedarii and Hyalomma impeltatum species collected on camels. Even if dromedary camels represent <3% of the domesticated ruminants in the countries of the Mediterranean basin Southern coast, these animals play a major socioeconomic role for millions of people who live in the arid zones of Africa, Middle East, and Asia. In Chad and Somalia, camels account for about 7 and 21% of domesticated ruminants, respectively. To meet the growing consumers demand of camel meat and milk (>5 million tons/year of both raw and pasteurized milk according to the Food and Agriculture Organization) sustained by a rapid increase of population (growth rate: 2.26-3.76 per year in North Africa), dromedary camel breeding tends to increase from the Maghreb to the Arabic countries. Because of possible long-term persistence of C. burnetii in camel hump adipocytes, this pathogen could represent a threat for herds and breeding farms and ultimately for public health. Because this review highlights a hyperendemia of C. burnetii in dromedary camels, a proper screening of herds and breeding farms for C. burnetii is urgently needed in countries where camel breeding is on the rise. Moreover, the risk of C. burnetii transmission from camel to human should be further evaluated.

Ruminant pestiviruses in North Africa

Ruminant pestiviruses are widely distributed worldwide, causing congenital disease and massive economic losses. Although ruminant production is an important economic sector in North Africa, the knowledge about pestiviruses is scarce. The present study aimed at assessing the presence of Pestivirus in cattle in Algeria, and to review the data available on ruminant pestiviruses in North Africa. A cross-sectional study was conducted on dairy farms from North-Western Algeria. Blood samples from 234 dairy cattle from 31 herds were collected. All sera were analysed for the presence of antibodies using a commercial iELISA. The presence of Pestivirus RNA was also assessed by using a Reverse Transcription-PCR, and PCR-positive samples were sequenced. Risk factors related to Pestivirus infection were also analysed. The review of the presence of ruminant pestiviruses in North Africa was performed using a systematic search and compilation methodology of the peer-reviewed literature available in order to identify gaps of knowledge for future research. The seroprevalence at population and farm levels obtained in the present study (59.9% and 93.5%, respectively) concur with data reported in neighbouring countries. Risk factors associated with Pestivirus infection in cattle were the presence of sheep in the herd and the animal category (cow vs heifer). Furthermore, we confirmed the presence of BVDV-1a in Algeria. The scarce data suggest an endemic epidemiological scenario of pestivirus in livestock. The lack of studies about the epidemiology and molecular variability of ruminant pestiviruses in livestock and wildlife in North Africa is of concern for animal health and wildlife conservation, and needs to be addressed.

Bovine viral diarrhea virus: An updated American College of Veterinary Internal Medicine consensus statement with focus on virus biology, hosts, immunosuppression, and vaccination

Control of bovine viral diarrhea virus (BVDV) in cattle populations across most of the world has remained elusive in spite of advances in knowledge about this viral pathogen. A central feature of virus perseverance in cattle herds is the unique mechanism of persistent infection. Managing BVDV infection in herds involves controlling persistently infected carrier animals using a multidimensional approach of vaccination, biosecurity, and identification of BVDV reservoirs. A decade has passed since the original American College of Veterinary Internal Medicine consensus statement on BVDV. While much has remained the same with respect to clinical signs of disease, pathogenesis of infection including persistent infection, and diagnosis, scientific articles published since 2010 have led to a greater understanding of difficulties associated with control of BVDV. This consensus statement update on BVDV presents greater focus on topics currently relevant to the biology and control of this viral pathogen of cattle, including changes in virus subpopulations, infection in heterologous hosts, immunosuppression, and vaccination.

Considerations for the development of a dromedary camel (Camelus dromedarius) semen collection centre

The dromedary camel (DC) is a strategic animal for the exploitation of the desert and unhospitable lands (arid and semiarid areas). These animals are a genetic resource, locally adapted and more resilient to these environs, that may significantly contribute to food security and sustainable development of marginal land areas. Artificial insemination is the least invasive, least expensive technique for improving genetic selection and minimising transmission of venereal disease among animals and herds. Besides semen preservation protocols, specific approaches for the development of DC semen collection centres - biosecurity measures, screening for infectious diseases, management of animals, welfare, nutrition, control of seasonality, training, hygiene of semen collection and processing - have been considered less important aspects. The aim of this research is to describe the aspects related to the development of a DC semen collection centre, summarising the latest studies in the field of welfare, reproduction and diseases, and describing biosecurity and hygiene aspects related to semen collection and handling. Scientific gaps and requirements for maximising the production of good quality and safe-to-use semen doses with minimal risks of disease transmission are also described.

Seroprevalence of bovine leukemia virus in cattle, buffalo, and camel in Egypt

Bovine leukemia virus (BLV) is the causative agent of enzootic bovine leukosis. It causes significant economic losses associated with losses due to slaughter and eradication of infected animal from infected area and other indirect economic losses such as restriction on importation of animals and semen from infected area. The main objective of this study was to determine the seroprevalence of BLV antibodies in cattle, buffaloes, and camels in Egypt using ELISA test. Serum samples were collected from 350 cattle, 100 buffaloes, and 100 camels during 2018. The seropositivity for BLV-specific antibody was 20.8%, 9%, and 0% in cattle, buffaloes, and camels, respectively. The result revealed significant association (p < 0.05) between age and seroprevalence of BLV infection in cattle > 4 years (24%) compared with those < 4 years (13%). We found no significant association between pregnancy and herd size and seroprevalence of BLV infection in this study (p > 0.05). Furthermore, the age, pregnancy state, and herd size had significant effect on seroprevalence of BLV infection in buffaloes. This study contributes that BLV is detected in cattle and buffaloes in Egypt and confirms that the camels has resistance against BLV infection. Hence, the control measures are very necessary to combat the transmission of the disease and reduce its economic impact.

Epidemiological surveillance of bovine viral diarrhea and rift valley fever infections in camel

Aim:

This study was designed to investigate the current epidemiological situation of bovine viral diarrhea virus (BVDV) and rift valley fever virus (RVFV) infection of camels originating from Sudan “smuggler” and Egypt as part of our future plan for a national surveillance program in Egyptian provinces, which will aid in establishment of control strategy for animal diseases.

Materials and Methods:

This investigation was accomplished using serological diagnostic and molecular biology techniques. A total number of 200 blood samples were collected from camel (120 originated from Sudan “smuggler” and 80 from local breed) and were subjected for testing both BVDV and RVFV occurrence with different age and sex.

Results:

Sixty-six of the 200 camels (33%) were positive for BVDV antibodies, and 44 (22%) for BVDV antigen (Ag), and 27 of the 200 camels (13.5%) were positive for RVFV immunoglobulin G (IgG) antibodies. On the other hand, the seroprevalence of BVDV for antibodies (47.5%), Ag (31.6%), and RVFV IgG antibodies (16.6%) was higher in camel originated from Sudan “smuggler” than of local breed which was 11.2% for BVDV antibodies and 7.5% for BVDV Ag, while it was 8.7% for RVFV IgG antibodies. The incidence of BVDV antibodies, Ag, and RVFV IgG antibodies was the highest in male, up to 9 years of age. The frequency of positive cases was significantly different according to the origin of samples and sex and age of camel for BVDV and RVFV. In addition, seven serologically positive samples for BVDV and five serologically positive samples for RVFV were submitted as a buffy coat for molecular detection by one-step – reverse transcription polymerase chain reaction (RT-PCR). The results demonstrated that three samples were positive for BVDV of camel originated from Sudan (smuggler), while no RVFV Ag was detected in all five samples. Sequencing and phylogenetic analysis of the amplicons obtained from positive RT-PCR samples (three samples) indicated 100% nucleotide homology with Sudan strain 2015 except only one (missense point mutation) by substitution of A to T at position 345 that changed the coded amino acids from T (Threonine) to S (Serine) at residue 115.

Conclusion:

Camels act as risk animals for the introduction of many infectious diseases from Sudan to Egypt, especially transboundary animal diseases, so strict quarantine measures should be taken during importation of live animals from Sudan to prevent the spread of such diseases.