The burden of HEV outbreak is reflected by proportional morbidity from HEV at facilities and in communities. A median number of 34 cases were reported daily, female patients were observed to be more likely to be affected by the HEV outbreak. A study in Northern Namibia indicates that among patients with HEV male patients predominated over female cases 2.5:1 . This distribution in females might be attributed to more severe clinical presentation in women, especially those who are pregnant [3, 8, 14]. High proportions of cases (43.7%) were adults aged between 18 and 30 years, this may be due to the culture differences where adults mainly search for livelihoods . Contrary to these findings, in a study carried out in North India  showed 3.8% of the cases were aged below 5 years, indicating that also under-fives are at risk of HEV.
The high case fatality rate in the study (2.2%) is higher than that reported earlier in Uganda in 2008 (1.5%) , but lower than that reported in Darfur in 2004 (1.7%) . With proper case management a lower CFR (<1%) could have been achieved . This is likely to be due to frequent migration between dry seasons, in search for settlement areas. In this study, extremely high CFR of 65.2% was reported among pregnant women. This is higher than the 48% reported in sporadic cases in Ethiopia  and the 12.5% reported in Kenya in 2012 . Differences in environmental factors and lack of community awareness on harmful traditional medicine like the use of local herbs to treat some complications during pregnancy could have contributed high CFR. Lorengechora being a town council, cases were most likely to be transmitted by eating roadside food [1, 2, 9]. With unsanitary food handling methods and exposure to many people, risk for HEV would be high. Ngolereit is in the north, neighboring Moroto, a very highly nomadic setting, movement could have enhanced transmission of HEV virus evidenced by number of cases reported out.
The epidemic curve was multimodal and suggestive of a propagated point source common vehicle epidemic, with the largest peak registered in the 48th epidemiologic week. Temporal peaks occurred during the 43-48th epidemiological week, coinciding with the rainy season and flooding in January. Flooding could have carried away any potential fecal substances causing contamination. Studies done in Ethiopia 2012 , and Uganda [2, 3] showed high proportions of cases occur in a dry season.
Risk factors for HEV outbreak
At multivariate analysis, HEV was significantly associated with eating roadside food, drinking untreated water, failure to wash utensils and being a hunter (Table 4). All these factors suggest that in this study, HEV was transmitted by the feco-oral mechanism through a waterborne route, which is typical of genotype 1 and genotype 2 as previously reported by different studies [2, 7].
The odds of having hepatitis E increased by six times among those eating roadside food. Roadside foods are easily contaminated because of unsanitary food handling methods and exposure to many people and winds. Study carried in Europe , confirmed food borne contamination in food handler working in a restaurant with high at risk foods.
Drinking untreated water increased the risk of HEV by almost seven times amongst the cases. This suggests that there was prior contamination of water sources and possible water-borne transmission in Napak district. This is not surprising since the situation regarding water and sanitation in this setting is very poor, this finding is confirmed elsewhere [20–22]. However, no associations with poor water and sanitation situation are reported in sporadic cases Turkmenistan . Not cleaning utensils increased the risk of HEV by more than three times among the cases, unclean utensils could have acted as a reservoir for HEV. This situation was attributed to distant water sources and the scarcity of water in the areas. Cases were more likely to travel outside their homes although this finding was not significantly associated with HEV perhaps due to small numbers in strata. Previous studies have linked HEV to travel [19, 20].
Frequent travelers revealed a history of visiting an endemic country with high-risk enteric exposures prior to infection. In this study, the HEV epidemic is attributed to the nomadic livelihoods of the people in search for water, and life in camps during the dry seasons [2, 8, 19].
Unlike previous reports , having more than five members (larger family size) in the household was not significantly associated with HEV. These findings concur with the previous HEV outbreak in Uganda, which did not find any significant association with household size . The findings in recent outbreaks in Uganda and studies done in rural Bangladesh [7, 23] and in India  demonstrated a strong role of person-to- person transmission in sustaining the epidemic . In this study it was not evident but may have occurred. Use of unsanitary latrines i.e. like open defecation was associated with HEV at bivariate but not at multivariate analysis, perhaps due to small numbers in the strata. However previous studies from Nepal-India and Uganda confirmed a strong association between use of unsanitary latrines and HEV most probably due to fecal matter being easily washed to water sources [17, 24].
HEV was associated amongst those who reported not washing hands with soap after defecation, whose primary source of water was a well, Promiscuous defecation and improper disposal of children’s feaces could have contributed to the situation. Attending social events was significantly associated with HEV at bivariate but not at multivariate analysis.
Social events like birth ceremonies, funeral ceremonies, visiting shrines and marriages can cause transmission of disease particularly through contaminated food and water [2, 11]. About 40 cases of jaundice were reported among people who attended a traditional function in Lorikitae village, in Matany Sub County. In this study, livestock ownership was high and contact with animals was common. Participants reported owning pigs (6.5%), cattle (31.8%), goats (27.9%) and chicken (34.3%).
Use of Cow dung’ is common, this practice consists of drying the cow dung into pieces which are then heated then used as a preservative for Beans and ataapa (Millet), what remains used for cooking. The same cow dung while still wet is used for construction of houses (Manyatas), these are considered potentially hazardous.
However, there was no significant association between HEV and livestock ownership or contact with animals at multivariate analysis. This contrasts the study done in Ghana, which reported 37% sero-prevalence in pig handlers, suggesting that the predominant HEV genotype were zoonotic [7, 25].
The less educated were more likely to confound not washing utensils. They reported poor hygiene practices, unsanitary disposal of fecal matter and also they never had permanent sources of water. Contamination was possible in these groups during the wet seasons. Hunters who had reported frequent movents were at a higher risk of HEV compared to their to their counterparts who had no occupation.