Schistosoma mansoni in migrants entering South Africa from Moçambique--a threat to public health in north-eastern KwaZulu-Natal?

OBJECTIVES

To identify possible public health consequences of Schistosoma mansoni infections in migrants entering north-eastern KwaZulu-Natal and Mpumalanga and Northern Province from southern Moçambique.

DESIGN

(i) Intestinal parasite surveys, one sample per person, within a 4-month period; (ii) temperature recordings and snail collections in an irrigation system.

SETTING

North-eastern KwaZulu-Natal and Kruger National Park, Mpumalanga and Northern Province.

PARTICIPANTS

Ninety-seven migrants (1-68 years) from north-eastern KwaZulu-Natal and 47 from the Kruger Park (1 - 70 years).

MAIN OUTCOME MEASURES

The relatively high S. mansoni prevalence may cause problems on the rice paddy scheme in north-eastern KwaZulu-Natal. Ranges and prevalence rates of other parasites were recorded.

RESULTS

S. mansoni prevalence in Moçambicans entering north-eastern KwaZulu-Natal was 14.4%, seven times more than in local residents. S. mansoni is not endemic to this region because most bodies of water become too warm for either the parasite or its snail host, Biomphalaria pfeifferi, to develop. Recordings in paddies suggest, however, that the rice modifies the temperature pattern as it grows and provides a suitable habitat for transmission. Migrants entering the Transvaal lowveld where S. mansoni is endemic may become more severely infected. Thirteen other parasite species were recorded from migrants entering KwaZulu-Natal and 8 from those entering Mpumalanga and Northern Province.

CONCLUSIONS

The relatively high S. mansoni prevalence among migrants entering north-eastern KwaZulu-Natal may have public health implications as it could encourage transmission in a non-endemic area. The range of parasites carried by migrants entering KwaZulu-Natal, Mpumalanga and Northern Province was similar to that harboured by local people but prevalence rates were generally lower.