Seroprevalence of camel brucellosis (Camelus dromedarius) in Somaliland

Serosurvey and associated risk factors for Chlamydia abortus infection in Dromedary camels in Egypt

Chlamydia abortus (C. abortus) is a gram-negative, obligate intracellular bacterium that causes major public health problems in human and reproductive problems in animals. The information about the epidemiology of this pathogen among camels in Egypt is very rare. This study aimed to evaluate the existence of antibodies against C. abortus in camels and assess the related risk factors for infection. A total of 410 blood samples were collected from camels from three Egyptian governorates and examined using commercial ELISA kit. The overall seroprevalence rate was 6.6% and the higher C. abortus seropositivity rate was found in Giza governorate. Location, sex and infestation by ectoparasites did not influence on the seroprevalence of the disease. In addition, age, herd size, contact with small ruminants and history of abortion were identified as risk factors for C. abortus infection according to the univariate analysis. Based on multivariate analysis, age group of 4-8 years, small herd size, contact of camels with sheep and goats, and history of abortion were found to be significant risk factors for chlamydiosis transmission in camels. These factors had odds ratios of 4.23, 3.51, 2.84, and 2.5, respectively. These results suggest that camels have a role in the epidemiology of C. abortus infection. This promotes awareness and severe public health concern about infectious camel illnesses, allowing for additional diagnostic advancements and effective management techniques to be developed.

Serological and molecular survey of brucellosis and chlamydiosis in dromedary camels from Tunisia

The present sero-epidemiological survey was designed and conducted to scrutinize the current status of camel-related brucellosis and chlamydiosis in Tunisia. Whole blood and serum samples were collected from 470 dromedaries (Camelus dromedarius) from eight different Tunisian governorates. Serum samples were subjected to indirect enzyme-linked immunosorbent assay (iELISA). The detection of Brucella and Chlamydia DNA was performed using conventional PCR targeting the bcsp-31 and 16 S rRNA gene, respectively. Overall, 10/470(2.12%) and 27/470 (5.75%) camels were revealed seropositive to Brucella and Chlamydia, respectively. Multivariate logistic regression analysis showed different risk factors associated with these infections. Meaningful high rates of seropositivity of brucellosis (9.5%; p = 0.000; OR=64.193) and chlamydiosis (22.6%; p = 0.000; OR=42.860) were noted among camels showing previous abortions in particular for aged females. Besides, Chlamydia seropositivity is significantly important during winter (12.5%; p = 0.009; OR= 27.533), and in camels raised in small farms (11.4%, p = 0.000, OR=86.052). Molecular analysis revealed no positivity from all analyzed blood samples. These findings indicate the involvement of camels in the epidemiology of these abortive infectious diseases. This raises awareness and serious public health concern for infectious camel diseases in order to develop further diagnostic improvements and effective control strategies.

Zoonoses research in Somalia: A scoping review using a One Health approach

Zoonoses are likely to cause a substantial burden on both human and animal health systems in Somalia, given the close proximity between the pastoralist majority and their livestock. However, decades of instability leading to weak disease surveillance have meant that data on the burden of zoonoses is lacking. The aim of this scoping review was to assess and synthesize the available literature on the presence and burden of zoonoses in Somalia. We used keywords to search Web of Science for relevant publications. Studies were included if they contained relevant data on a zoonosis and were undertaken in Somalia or were undertaken in another country where exposure could reasonably be assumed to have occurred in Somalia (e.g., migrants/refugees, returning soldiers, exported animals). Studies were not included if they focused on Somali ethnic communities permanently living elsewhere or if zoonotic aspects were not considered. We extracted data on disease(s) reported, geographic focus, data reported (human, animal, environment), study design and author affiliation. A total of 22 zoonotic infections were documented in 76 publications. The most frequently studied diseases were Rift Valley Fever (n = 15, 17%), brucellosis (n = 13, 14%) and hepatitis E (n = 10, 11%). Around 30% of papers reported data from relevant populations outside Somalia. Only 18 papers undertook laboratory analysis within Somalia. Most papers reported data on humans (45%) and animals (36%) with limited research on the environmental domain. Descriptive studies (47%) dominated and most were led by non-Somali researchers (89% in first authors and 95% of last authors). This study highlights the need for well-designed zoonoses research in Somalia supported by capacity building of local researchers and investments in diagnostic laboratories.

Seroepidemiology of Camel Brucellosis in and around Dire Dawa, Eastern Ethiopia

Brucellosis is an infectious disease in domestic and wild animals with serious zoonotic and economic implication in humans, being more severe in developing countries. The disease is highly prevalent in cattle, camels, and small ruminants in pastoral and agro-pastoral areas in Africa. Here we have investigated the seroepidemiology of camel brucellosis in and around Dire Dawa, eastern Ethiopia, using a cross-sectional study design to determine the seroprevalence of the disease and to identify risk factors that would facilitate the transmission of zoonotic diseases to humans. This study involved testing 350 serum samples from camels and interviewing 120 livestock owners. The modified Rose Bengal plate test (mRBPT) and the complement fixation test (CFT) were used as screening and confirmatory tests, respectively. The overall sero-prevalence of camel brucellosis was found to be 8.3% and 2% using mRBPT and CFT tests, respectively. Among the risk factors assessed, only abortion and body condition disclosed a statistically significant difference (p < 0.05) with regard to the seropositivity of camel brucellosis. Camel brucellosis is prevalent in eastern Ethiopia and there is a need to execute well-organized disease control and prevention programs and exercise public health education to scale up awareness of the community towards the disease.

Prevalence of Anti-Toxoplasma gondii and Anti-Brucella Spp. Antibodies in Pregnant Women From Mogadishu, Somalia

Toxoplasmosis and brucellosis are zoonotic diseases of worldwide distribution. They both cause abortion and infertility in human and animals. Limited data are available about these pathogens in Somali people and their animals. Hence, this study has evaluated the prevalence of anti-Toxoplasma gondii and anti-Brucella spp. antibodies in pregnant women in Mogadishu, Somalia. Serum samples from 307 pregnant women from Mogadishu, Somalia were tested for anti-T. gondii antibodies by Latex Agglutination Test (LAT) and anti-Brucella spp. antibodies by Rose Bengal Plate Test (RBPT) and a commercial competitive-ELISA (cELISA). A total of 119/307 (38.76%) pregnant women had a prior history of abortion. A total of 159/307 (51.79%; 95% CI: 46.2–57.35%) pregnant women were seroreactive for T. gondii by LAT at different stages of pregnancy. For Brucella spp., when RBPT and cELISA were combined 4/307 (1.30%; 95% CI: 0.36–3.30%) pregnant women were seroreactive to anti-Brucella spp. antibodies, being 2/307 (0.65%; 95% CI: 0.18–2.34%) by RBPT and 3/307 (0.98%; 95% CI: 0.33–2.83%) by cELISA. Two women were seroreactive for both agents. A high seropositivity to T. gondii and low seropositivity to Brucella spp. have been found in pregnant women from Mogadishu, Somalia. Considering the high number of abortions in the country associated to the fact that awareness on other zoonotic abortifacient pathogens in Somalis is very low, further studies should be conducted to evaluate the potential causes of abortions.

Seroprevalence and Risk Factors Associated with Brucella Infection in Camels in the Puntland State of Somalia

Brucellosis is an important zoonotic disease caused by members of the genus Brucella. Camel brucellosis has been reported in almost all camel-rearing countries in Africa and Asia. A cross-sectional study was conducted between February 2020 and February 2021 in Galkayo, Garowe, and Bosaso districts in the Puntland State of Somalia to investigate the seroprevalence and risk factors of brucellosis in camels. A competitive enzyme-linked immunosorbent assay (c-ELISA) was used to detect anti-Brucella antibodies, while a structured questionnaire was used to collect epidemiological data. A total of 441 camel sera were screened against Brucella antibodies. Thirty-one (7%; 95% CI: 4.8–9.8%) samples were positive, and thirteen (54.2%; 95% CI: 32.8–74.4%) out of the twenty-four farms sampled had at least one seropositive animal. Galkayo district had the highest number of Brucella-seropositive camels (10.3%), followed by Bosaso district (8.6%), while Garowe district had the lowest number of seropositive camels (1.4%). The binary logistic regression model revealed that camels in Galkayo district (p = 0.015; OR: 9.428; 95% CI: 1.539–57.755), camels from large herd sizes of >50 animals (p = 0.019; OR: 5.822; 95% CI: 1.336–25.371), and those in contact with small ruminants (p = 0.011; OR: 10.941; 95% CI: 1.728–69.285) were significantly associated with seropositive cases of camel brucellosis in the Puntland State of Somalia. The present study shows that Brucella infections in camels are prevalent in the three districts covered by the study. This poses a public health risk, because milk from these camels is used for human consumption. Studies focusing on the isolation of Brucella strains in camels and investigating brucellosis in ruminants and humans are recommended in the study area. Validation of serological tests—including c-ELISA—for Brucella antibody detection in camels is also needed.

Isolation of Brucella melitensis from seronegative camel: potential implications in brucellosis control

Brucellosis is a significant zoonotic infection in Iran impacting both humans and animal health status. A number of reasons such as few clinical signs complicate the diagnosis of this infection in Camelidae. Despite the ubiquitous use of serological tests for the first screening of brucellosis in camel, this approach showed several restrictions because of the intracellular properties of this organism as well as decline antibody titers in chronic stage. This study aimed at identifying the presence of Brucella spp. in blood and lymph node samples collected from slaughtered male camels of Sistan-Baluchistan province by serology, culture and polymerase chain reaction (PCR) assay. For this purpose, 2854 blood camel samples were sampled and analyzed for Brucella detection by serological screening tests. The molecular detection of IS711 gene and Bruce-ladder assay as well as culture were performed using the lymph nodes of all seropositive camel (n = 10) and 30 seronegative samples. Results showed that 0.35% (10/2854), 0.24% (7/2854) and 0.21% (6/2854) of blood samples were positive by RBPT, SAT and 2ME, respectively. However, 0% (0/10) and 70% (7/10) of lymph node samples collected from seropositive camels were positive for Brucella infection by culture and PCR, respectively. Furthermore, 6.6% (2/30) of seronegative lymph node specimens showed the presences of Brucella by PCR and culture assay. The results of the present study indicated the low seroprevalence of Brucella infection in male camels of the Sistan-Baluchistan province and highlighted the complementary role of PCR techniques for a better screening of Brucella infection among seronegative camels. Moreover, the potential shedding of Brucella within undiagnosed camel milk and secretions is a serious problem which may result in further spread and maintenance of Brucella infection among both human and livestock. Thus, for brucellosis detection and control, our results suggested that a first PCR screening supported by a bacteriological isolation on positive samples should be performed along with the serological test in endemic countries to identify the source and prevent the uncontrolled spread of the disease among camels.

Sero-prevalence and community awareness on the risks associated with Livestock and Human brucellosis in selected districts of Fafan Zone of Ethiopian-Somali National Regional State

A cross-sectional study was conducted to estimate the sero-prevalence, potential risk factors for transmission and spread of brucellosis in livestock and human in Jigjiga and Gursum Woredas of Fafan Zone in Ethiopian-Somali. Two Kebeles were purposively selected from each Worada based on accessibility and willingness of livestock owners. For serology, a total of 268 cattle, 108 sheep, 172 goats, 183 camels, 211 humans were included. For questionnaire, 99 volunteers were recruited. Blood samples were collected from livestock and human. The serum was subjected to Rose Bengal Plate Test (RBPT) and Complement Fixation Test (CFT) to detect Brucella antibody. Out of the total 731 livestock examined, 3.0% were positive for Brucella antibodies using RBPT. Highest sero-prevalence was recorded in camels (4.9%) followed by goat (2.9%), cattle (2.6%), and sheep (0.9%). Using CFT, 0.4% of animals were found positive for brucellosis. A sero-prevalence of 1.7% was recorded in goats using CFT but no in other animal species. From the 211 human serum samples, 5 (2.4%) were positive for Brucella infection using RBPT. One (0.4%) was confirmed by CFT. Questioner survey revealed, almost all respondents (98%) were not aware about zoonotic risks of brucellosis. Cattle and camel milking were mainly performed by housewives. Although 97-99% of respondent had habits of cooked meat consumption, the majorities (99%) consume raw milk. In the pastoral community, the observed sero-prevalence of human brucellosis along with the practices of animal husbandry and animal food consumption habits, might give an insight that brucellosis could pose a public health hazard.

Serological, molecular detection and potential risk factors associated with camel brucellosis in Pakistan

Brucellosis is one of the most important zoonoses in developing countries and was considered the most widespread zoonosis in the world. Brucellosis was reported in camels and has been reported from all camel-keeping countries.The present study was performed in three districts (Jhang, Chiniot, and Bhakkar) of Punjab province of Pakistan. A total of 200 camel (Camelus bactrianus) sera were collected using random and multistage cluster sampling from different areas. Fifty samples were collected from one organized governmental farm. One hundred fifty samples were collected randomly from nomadic/pastoral production systems. All sera were tested with Rose Bengal plate agglutination test (RBPT) and confirmed by ELISA. Genomic DNA was extracted from all serum samples and tested by real-time PCR. Various potential risk factors (season, rearing with other animals, and abortion or orchitis history) recorded through questionnaires were statistically analyzed by Chi-square test.In total, 5 % of investigated sera were positive by RBPT. Only 2 % of the camel sera were CELISA positive. Brucella abortus DNA was detected in 1.5 % of the investigated animals. Season, rearing of camels with other ruminants, abortion, and orchitis history were found to be statistically significant (p < 0.05) disease for determinants.Camel brucellosis is a zoonotic disease in the Pakistani Punjab with various risk factors maintaining and perpetuating its spread. Therefore, there is a need for implementing control measures and raising public health awareness in prevention of brucellosis in Pakistan.

Seroprevalence and risk factors for brucellosis in cattle in selected districts of Jimma zone, Ethiopia

A cross-sectional study was carried out in Jimma town and Chora Botor district of Jimma zone from February 2014 to May 2014 to determine seroprevalence and risk factors of brucellosis in cattle. A total of 348 blood samples (174 each from zebu and crossbreed) were collected. The sera were separated and screened by Rose Bengal plate test (RBPT), and positive sera were retested by complement fixation test (CFT) for confirmation. The overall seroprevalence of bovine brucellosis was 1.4 and 0.3 % as tested by RBPT and CFT, respectively. The seroprevalence of bovine brucellosis in indigenous and crossbreed cattle was 1.1 and 0.6 % and 1.7 and 0 % using RBPT and CFT, respectively. Retained fetal membrane was the only risk factor found to be significantly associated with seropositivity of brucellosis in this study (p = 0.019). The overall seroprevalence of brucellosis was very low. However, due to the zoonotic and economic importance of the disease, prevention and control measures are required to stop further spread of the disease. To effectively implement this, the One Health (OH) is the most constructive approach we recommend.

Camelus dromedarius brucellosis and its public health associated risks in the Afar National Regional State in northeastern Ethiopia

BACKGROUND

A cross-sectional study was carried out in four districts of the Afar region in Ethiopia to determine the prevalence of brucellosis in camels, and to identify risky practices that would facilitate the transmission of zoonoses to humans. This study involved testing 461 camels and interviewing 120 livestock owners. The modified Rose Bengal plate test (mRBPT) and complement fixation test (CFT) were used as screening and confirmatory tests, respectively. SPSS 16 was used to analyze the overall prevalence and potential risk factors for seropositivity, using a multivariable logistic regression analysis.

RESULTS

In the camel herds tested, 5.4% had antibodies against Brucella species, and the district level seroprevalence ranged from 11.7% to 15.5% in camels. The logistic regression model for camels in a herd size > 20 animals (OR = 2.8; 95% CI: 1.16-6.62) and greater than four years of age (OR = 4.9; 95% CI: 1.45-16.82) showed a higher risk of infection when compared to small herds and those ≤ 4 years old. The questionnaire survey revealed that most respondents did not know about the transmission of zoonotic diseases, and that their practices could potentially facilitate the transmission of zoonotic pathogens.

CONCLUSIONS

The results of this study revealed that camel brucellosis is prevalent in the study areas. Therefore, there is a need for implementing control measures and increasing public awareness in the prevention methods of brucellosis.

A review on camel brucellosis: a zoonosis sustained by ignorance and indifference

In many developing countries of Asia and Africa, camels are one of the most important sources of income for the nomadic population. With increasing urbanization, camel milk and meat have gained a wider market and commercialization and consumption of camel products are on the rise. Camel brucellosis can be encountered in all camel rearing countries with exception of Australia. High animal and herd prevalences have been reported from numerous countries, which not only pose a continuous risk for human infection, but also increase the spread of infection through uncontrolled trade of clinically inconspicuous animals. This short review aims at providing an overview on diagnostic investigations, as well as the public health and economic impact of brucellosis in old world camels.

Seroepidemiological study of livestock brucellosis in a pastoral region

A seroepidemiological study of Brucella infections in multiple livestock species in the Borana pastoral system of Ethiopia was performed between December 2007 and October 2008. A cross-sectional multi-stage sampling technique was employed to select 575 cattle, 1073 camels and 1248 goats from the target populations. Sera were collected from the animals, and serially tested using Rose Bengal test and complement fixation test. Overall prevalence and prevalence with respect to explanatory variables were established, and potential risk factors for seropositivity were analysed using a multivariable logistic regression. The results showed that 8·0% (95% CI 6·0–10·6), 1·8% (95% CI 1·1–2·8) and 1·6% (95% CI 1·0–2·5) of the tested cattle, camels and goats, respectively, had antibodies to Brucella antigen. Positive reactors were found in 93·8% of the villages with more frequent detection of positive cattle (93·3%) than camels (56·3%) and goats (37·5%). Risk factors identified for cattle were: keeping more livestock species at household level (OR 4·1, 95% CI 1·9–8·9), increasing age of the animal (OR 2·8, 95% CI 1·3–6·0) and wet season (OR 3·3, 95% CI 1·6–6·9). Increase in household-level species composition (OR 4·1, 95% CI 1·2–14·2) and wet season (OR 3·7, 95% CI 1·5–9·1) were found to be risk factors for seropositivity in camels and goats, respectively. Existence of more than one seroreactor animal species in most villages and association of increased livestock species composition with seropositivity may add more credence to the possibility of cross-species transmission of Brucella infections. Although no attempt to isolate Brucella spp. was made, our results suggest that cattle are more likely maintenance hosts of Brucella abortus which has spread to goats and camels. This should be substantiated by further isolation and identification of Brucella organisms to trace the source of infection and transmission dynamics in various hosts kept under mixed conditions. In conclusion, the present study suggests the need for investigating a feasible control intervention and raising public awareness on prevention methods of human exposure to brucellosis.

Brucellosis at the animal/ecosystem/human interface at the beginning of the 21st century

Following the recent discovery of new Brucella strains from different animal species and from the environment, ten Brucella species are nowadays included in the genus Brucella. Although the intracellular trafficking of Brucella is well described, the strategies developed by Brucella to survive and multiply in phagocytic and non-phagocytic cells, particularly to access nutriments during its intracellular journey, are still largely unknown. Metabolism and virulence of Brucella are now considered to be two sides of the same coin. Mechanisms presiding to the colonization of the pregnant uterus in different animal species are not known. Vaccination is the cornerstone of control programs in livestock and although the S19, RB51 (both in cattle) and Rev 1 (in sheep and goats) vaccines have been successfully used worldwide, they have drawbacks and thus the ideal brucellosis vaccine is still very much awaited. There is no vaccine available for pigs and wildlife. Animal brucellosis control strategies differ in the developed and the developing world. Most emphasis is put on eradication and on risk analysis to avoid the re-introduction of Brucella in the developed world. Information related to the prevalence of brucellosis is still scarce in the developing world and control programs are rarely implemented. Since there is no vaccine available for humans, prevention of human brucellosis relies on its control in the animal reservoir. Brucella is also considered to be an agent to be used in bio- and agroterrorism attacks. At the animal/ecosystem/human interface it is critical to reduce opportunities for Brucella to jump host species as already seen in livestock, wildlife and humans. This task is a challenge for the future in terms of veterinary public health, as for wildlife and ecosystem managers and will need a "One Health" approach to be successful.