Our personal observation during surveys was that herders shake Acacia trees in order to make fruits fall, thus disturbing the suspected vector habitat and increasing the probabilities of being bitten. One important limitation of our study is its cross sectional nature, which limits the making of causal inferences between the analysed factors and the infection. surveyed 56 children were positive to infection (9.9%). The individual variables that showed a Necrostatin 2 positive association with infection were increasing age, being male and sleeping outside [adjusted odds ratios (95% CI): 1.15 (1.03, 1.29), 2.56 (1.19, 5.48) and 2.21 (1.03, 4.71) respectively] and in relation to the household: past history of VL in the family, living in a straw roofed house and if the family owned sheep [adjusted OR (95% CI): 2.92 (1.25, 6.81), 2.71 (1.21, 6.07) and 4.16 (1.41, 12.31) respectively]. Conclusions/Significance A behavioural pattern like sleeping outside is determinant in the transmission of the infection in this area. Protective measures should Necrostatin 2 be implemented against this identified risk activity. Results also suggest a geographical clustering and a household focalization of the infection. The behaviour of the vector in the area needs to be clarified in order to establish the role of domestic animals and house materials in the transmission of the infection. Author Summary Visceral leishmaniasis is a vector borne disease that can be fatal if left untreated. Its prevalence is steadily rising in northern Ethiopia posing a public health challenge in the region. We conducted a study on the factors associated to asymptomatic infection in Libo Kemkem and Fogera, Amhara regional state, where little is known about transmission. Sleeping outside was identified as a risk activity so measures towards it are recommended. Our results also showed a geographical clustering and a household focalization of the infection although the reasons behind it are not clearly understood. More entomological studies are needed in order to clarify the vecto’s behaviour in the area. Individuals living in houses that owned sheep were more likely to be infected but no association was found with other domestic animals like cattle chicken or dogs. These results add up to the debate found in the literature regarding the role of domestic animals in the transmission of in different regions of the world. No specific recommendation should be given until the exact role of the domestic animal in the transmission cycle is clearly understood. Introduction Visceral leishmaniasis (VL) or kala-azar is a neglected vector-borne parasitic disease that manifests with irregular bouts of fever, substantial weight loss, weakness, hepatosplenomegaly and pancytopenia, and that is fatal if left untreated . It has an estimated annual incidence of 500 000 clinical cases with 50 000 associated deaths and 2 357 000 disability-adjusted life years lost . It is mainly concentrated Necrostatin 2 in few major foci and the East African focus is the second largest, with the highest incidence in Ethiopia and the Sudan . VL is caused by protozoan parasites of the complex transmitted to human and animal hosts by the bite of phlebotomine sand flies. It has already been determined that large numbers of individuals in endemic areas are infected with the parasite but do not develop any signs or symptoms of the disease. The reported ratio of asymptomatic infections to VL clinical cases varies widely from 41 in FN1 Kenya  to 501 in Spain . This variation is presumed to reflect differences in parasite virulence and host population characteristics, and may also Necrostatin 2 depend on the study designs and on the tests used to define asymptomatic infection . The methods more widely used in order to assess asymptomatic infection in the field are a) serological assays that detect anti-antibodies based either on the direct agglutination test (DAT) or the rK39-immunochromatographic test (rK39-ICT) and b) Leishmanin Skin Test (LST) that measures cell-mediated immunity against infection among the villages with high incidence of VL in Libo Kemkem and Fogera in order to complement the already existing information on VL transmission in the area and help the Amhara regional health authorities to develop effective strategies to control the transmission of the disease. Materials and Methods Study area and population The study was conducted during MayCJuly 2009 in the districts (77(2), 2007, pp. 275C282. Study design The study was carried out within the framework of a UBS Optimus Foundation funded project called Visceral Leishmaniasis and Malnutrition in Amhara.