Risk factors and socioeconomic effects associated with spread of peste des petits ruminants (PPR) in Turkana county, Kenya
Livestock keeping is the main source of livelihood for most pastoral households found in arid and semi arid lands (ASAL) of Kenya which are characterized by prevalence of diseases, extreme climatic features of drought, flooding, low investments, fragile ecosystems and high poverty levels as challenges to the pastoral livestock sector growth. Small stock keeping is one of the major livelihood activities for the pastoral communities which contribute heavily to pastoral household subsistence and market income. A major constraint to small stock keeping is emerging viral diseases including PPR that is a relatively new, highly contagious and often fatal disease of sheep and goats that has caused devastating losses in Kenya since it was first officially reported in 2007 in the Turkana County. Peste des petit ruminants has since spread to almost all ASAL pastoral counties in Kenya. Efforts to control the disease in Kenya have been limited due to lack of epidemiological information while the risk factors and socio-economic effects associated with the spread of the disease in Turkana District are not fully known. As such it has not been clear how effective the control activities implemented had been in stemming the spread of the disease in Kenya. The general objective of the study thus was to assess the risk factors and socio-economic effects associated with the spread of PPR in Turkana County, while the specific Determine the disease socio economic impact and (4) Document and evaluate the control strategies of the disease in Turkana County of Kenya. The risk factors associated with the spread of PPR in Turkana County were identified using participatory epidemiology (PE) methodologies. The data on community participatory appraisal of PPR disease was validated with field pathological samples that were collected and the PPR virus RNA analyzed with qRT-PCR both in fresh frozen samples and formalin fixed tissues. Histology samples were also examined for pathological lesions associated with PPR. Further participatory risk assessment questionnaires were used to determine community perception of PPR on the risk factors. The level of herd immunity was determined using serological methods namely cELISA tests to analyze in 969 serum samples (431 from sheep and 538 from goats) collected in six divisions of Turkana county that formed the study area. The socio economic impact of PPR in Turkana County was determined using data derived from PE methodologies, key informants interviews and secondary data. The current control strategies on PPR in Turkana Kenya were determined using participatory epidemiology methodologies and were subsequently documented. A stochastic PPR compartmental model comprising maternal antibody, susceptible, exposed, infectious and recovered was developed based on field parameters; it was then used to evaluate the appropriateness of vaccination Results of PE exercises showed that the Turkana community was in agreement that PPR in sheep was associated with migration (p<0.001), herd mixing (p<0.001), raids (p<0.001), and dry season (p<0.01) while in goats PPR was associated with migration (p<0.001), herd mixing(p<0.001), raids (p<0.001), mountain pastures (p<0.001) and dry season (p<0.001) . However the risk factors significantly associated with the spread of PPR in Turkana County were sharing of water points with odds ratio of 2.022 (p<0.001) particularly during wet season of 2009. Sick nursing mothers were also identified as risk factor during the wet season of 2010 with odds ratio of 1.621 (p<0.049). In a subsequent sero-epidemiological study species was significantly associated with presence of PPR antibodies in a mixed herd of sheep and goats and thus considered risk factors where goat had Odds ratio= 1.644; (p<0.001). Unvaccinated sheep had odds ratio of 4.24 (p<0.000) compared to the vaccinated sheep while adult goats had odds ratio of 2.381 (p<0.003) in relation to kids for association with presence of PPR antibodies. The level of herd immunity within the flocks in Turkana was found to be 39.6% in goats which was significantly (p<0.001) higher than that of sheep at 31.6%. In both species, middle aged group between 6 months and 24 months were found to have low seropositivity of between 14.2% and 18.2% rendering this group vulnerable during PPR outbreak. The sero-epidemiological survey established that high demographic changes in Apart from drought, livestock diseases were the second most important factor that disrupt livestock livelihood with PPR being ranked as the disease with highest destructive impact on the small stock benefits to the Turkana community. The socio economic impact of PPR was found to be enormous in that it threatens to destroy sheep and goats that constitute the largest herd of livestock reared; their herd composition ranging between 42% and 64.4% of the total animal kept across the wealth groups. Lose of small stock would in essence destroy a source of animal food products which constitute 29.4% of all the food consumed by a Turkana household and is mainly consumed by the youthful workforce of morans and girl herders in the age group 13 to 18. The study established that the direct economic losses due to PPR in Turkana County alone for the year 2010 were in the tune of Kenya Shillings 11.1 billion. The current control strategies on PPR in Turkana County, Kenya have been found to be mainly local methods of using herbs as well as reducing contact between sick herds and healthy herds. Local methods that reduced animal contacts such as running away from sick herds and local sanctions such as restricted movement or/and access to public water points and pastures were consistent with scientific control method of creating sanitary belts. Vaccination was perceived to be among the most effective control method but was not easily accessed and the community had little knowledge about it; thus was ranked lowly among other control methods.