Malaria and Salmonella
infections: cause or coincidence?
AMMAH et al. (1999: Transactions, 93, 127) have reported an association between malaria and Salmonella infections from Cameroon. The association was particularly evident for Salmonella typhimurium infections, the majority of which occurred in children. All S. typhimurium isolates were from stool samples, and yet the authors have proceeded to discuss the possible pathogenesis with reference to the previously reported association between malaria and Salmonella bacteraemia (OBEY et al., 1987: Journal of Infectious Diseases, 155, 13 19). This is confusing as they have not attempted to differentiate between intestinal infection and invasive (or extraintestinal) disease. AMMAH et al. have implied that increased occurrence of intestinal salmonellosis and malaria in the same patients is due to alterations of host factors by malaria to increase susceptibility to intestinal salmonellosis. The conclusion of MABEY et al. was that malaria increases susceptibility to invasive disease, not intestinal infection.
The epidemiology of non-typhoidal Salmonella (NTS) infection for African children is not well known. An increase in intestinal salmonellosis has been noted in non-malarious tropical countries during the wet season, particularly in young children (HADDOCK & MALILAY; 1986: Toumal of Diarrhoeal Diseases Research. 4. 229). The study period for the report of AMMAH et ai covered both the rainy and the dry seasons, yet no mention is made of seasonal influence. As the wet season is the peak season for malarial infection in the same age-group, then an association between intestinal salmonellosis and malaria may be coincident.
NTS species, such as S. typhimurium, do cause gastroenteritis, as the authors state on a number of occasions. However, it is less widelv recoanized that NTS are an important cause of bacteraemia (GREEN & CHEES-