Prevalence survey of hydatidosis in Dagoretti, area, Nairobi, Kenya
A human hydatidosis prevalence survey was carried out in February/March 1995 in an area within the 2km radius about the Dagoretti abattoirs located in the borders of Nairobi Province and Kiambu District. This was done as a follow-up to a similar study done on "stray" dogs in this area. Using portable ultrasound scanner, a total of3,5 I8 volunteers were screened for hydatidosis. Sixty-five percent of these were children aged between 7 and 15 years. Serum samples were taken from those found "scan positive" for cystic hydatidosis, to be later confirmed by ELISA tests. Nine people were "scan positive" giving a prevalence of the disease of 0.26%. There was only one male out of the nine people who were "scan positive" for hydatidosis. The risk factors associated with human hydatidosis were sex, age and occupation. Females and those who fed and played with dogs had higher odds of infection than males and people who did not feed and play with dogs. Unexpectedly, pupils had lower odds of infection than other groups despite the fact that pupils reported more contacts with dogs. Of the livestock slaughtered at the Dagoretti abattoirs, about 60% were from Maasailand with cattle and sheep prevalences of hydatidosis of 30% and 19% respectively. The overall prevalences of hydatidosis for the cattle and sheep slaughtered in Dagoretti were 21.3% and 5.7% respectively. It was also noted that organs infested with hydatid cysts left abattoirs illegally. The human hydatidosis prevalence recorded in this study of 0.26% is low compared to 1% and 5% found in the endemic regions of Maasailand and Turkana District in Kenya respectively. However, this prevalence indicates that the presence of this disease in Dagoretti area is a new phenomenon and is likely to increase in the future. It is now clear that an urban domestic hydatidosis cycle is taking place at Dagoretti with different transmission dynamics from the rest of the known endemic regions of the country. Given that the dog echinococcosis prevalence (65%) in this area is very high, there is an urgent need for tightening the abattoir public health control measures and for initiating a public awareness campaign on the dangers of feeding raw offal to dogs.