Cross-Sectional Study of Brucellosis and Mastitis in Camels (Camelus Dromedarius) and Camel Milk Markets Network in Babille Woreda, East Harargae Zone, Ethiopia
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Date
2011-11-01
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Addis Ababa University
Abstract
A cross-sectional study was conducted with the objectives of determining the prevalence of camel brucellosis and clinical and sub-clinical mastitis and associated risk factors, and making a preliminary assessment of the camel milk markets network in Babille Woreda Field data gathering and observation was carried out from August to October, 2011. Two- stage cluster sampling was employed to select 378 camels in 12 peasant associations of Babille Woreda. Serum samples were taken from these camels and 8 serum samples (2.1 %) were lost during handling. The 370 sera were screened for brucellosis by RBPT and 26 serum samples (7.0%) were found positive and further tested by CFT where 9 sera (2.4%) were reacting positive.Hence, the overall seroprevalence was 2.4% (n=370). Seroprevalence of Brucella infection in male and female camels were 2.9% (7/241) and 1.6% (2/129) respectively, with no statistically significant difference. The seroprevalence of brucellosis was relatively higher (3.8%, n=791) in young (below 4 years) than in adult camels (above 4 years) (2.0%, n=291), however, not statistically significant. No statistical association of parity and origin of camels nor abortion with the occurrence of Brucella infection could be determined. All camels with an abortion history were reacting seronegative. Questionnaire survey results of 40 herders revealed an average herd size of 12.4 camels and camels were the only livestock in 8 of the herds (20%) and were reared together with other livestock in 80% of the herds. Contact with other herds was common in 90% of the herds. Abortion seemed rare in Babille Woreda: only 6 of the respondents (15%) reported abortion in the past. Fever, trypanosomosis infection, ingestion of toxic plants, drought and bulls were claimed to be the causes of abortion. For clinical and sub-clinical mastitis prevalence determination again two-stage sampling was undertaken and 544 quarters were examined from 136 lactating camels reared in 34 herds and 9 quarters were blind(1.7%). The remaining 535 quarter milk samples (98.4%) were screened for sub-clinical mastitis using CMT. Clinical examination of the udder and inspection of milk were employed to determine the presence of clinical mastitis; however, clinical mastitis was not observed at all. The prevalence of sub-clinical mastitis was 14.4% at quarter level. Sub-clinical mastitis cases were prevalent in 31 .6% of the camels studied. A significant association (p-< 0.05) was found between sub-clinical mastitis and age groups. Sub-clinical mastitis and udder lesions were also found to be significantly (p-< 0.05). The presence of sub-clinical mastitis was not significantly associated(p-<0.05).The presence of sub-clinical mastitis was not significantly associated with udder conformational disorders, tick infested udders and lactation stage classes. Out of a total number of 34 herds, 25 herds (73.5%) presented at least one camel with one quarter milk sample positive for CMT. Associations of practices of cauterization for treatment of udder problems, use of anti-suckling equipment and unhygienic practices with herd level sub-clinical mastitis positivity were not found . The questionnaire survey results showed that clinical mastitis seemed to be rare in the study area; only 4 owners(11.8%) confirmed the presence of mastitis in their herds. Twenty two respondents (64.7%) attributed the cause of mastitis in camels to tick infestation Cleaning of the udder before milking was seldom done, only 3 owners (8.8%) cleaned the udder. However, 31 owners (91.2%) washed their hands before milking.Through direct observation and interviews information was gathered to analyze the camel milk markets network in Babille Woreda and neighboring towns The nodes included all 22 PAs within Babille Woreda and 5 small and big towns to which the milk was; sold arcs represented milk trade relationship among PAs and of PAs and towns. A network with 27 nodes and 33 edges (relationships) was identified and analyzed. The network consisted of 3 components: one large component and two other components with 24, 2 and 1 nodes, respectively. The overall density of the milk market network was 0.047, indicating a very loosely connected network with an average degree of 1.2. Babille, Harer, and Jijiga scored high in-degree values indicating their role as terminal markets. Aw-Sherif having the highest degree centrality score had a very important and influential position in the network. There was substantial centralization in this whole network as the network centralization for out-degree and in-degree were 15.1 % and19.1 %, respectively. The network closeness centrality measures revealed that Harer had the highest incloseness score followed by Jijiga and Dire Dawa. The majority of the PAs had lower scores of closeness centrality measures as they were peripherally located. Actor betweenness measures ranged from zero to 20 with wide variation. Aw-Sherif,Erer Ibada and Gemechu appeared to be more powerful than others by this measure followed by Tula and Erer Guda and others scoring zero. This study has shown that camel brucellosis and sub-clinical mastitis are prevalent in the area. Both diseases can cause extensive economic losses in camel production and pose a public health hazard as a result of raw camel milk consumption and traditional husbandry practices. This is warranting control and prevention programmes and public health education. Such undertakings should be based on further in-depth epidemiological investigations. Network analysis of milk markets can help in policy formulations, evaluation of risks estimaion of potential spread of infectious agents and control as well as in designing and implementing risk-based surveillance and milk market devdopment activities
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Keywords
Dromedary camels, brucellosis, mastitis, network analysis, milk markets, Ethiopia