The prevalence and plasmid profile of non-typhoidal salmonellosis in children in Lagos metropolis, South-western Nigeria.

INTRODUCTION: Non-typhoidal Salmonella is the causative agent of gastroenteritis, a food-borne and zoonotic infection which is a major cause of high morbidity and death among children under 5 years of age especially from resource poor settings like the developing countries. METHODS: This study was carried out for 6 months to determine the prevalence and plasmid profile of non-typhoidal salmonellosis in children in Lagos metropolis. A total of 105 stool samples were collected from diarrheal children aged 3 months to 12 years and processed during this period. The isolates were identified using Selenite F Broth, Salmonella-Shigella Agar, Kligler Iron Agar, and Motility-indole-Urea medium, citrate and sugar utilization tests. RESULTS: A total number of 127 isolates were identified, 2 of which are Salmonella enteritidis (1.6%). The non-typhoidal Salmonellae were sensitive to ciprofloxacin, cetotaxime, streptomycin, cotrimxazole and tetracycline. Only one of the 2 isolates (50%) was sensitive to amoxillin and sulphonamide while none of them (0%) was sensitive to cefuroxime. CONCLUSION: The plasmid analysis of the isolates showed that they harboured no detectable plasmids; this suggests that the resistance was chromosomally mediated.

A retrospective study of community-acquired Salmonella infections in patients attending public hospitals in Lagos, Nigeria.

INTRODUCTION: A retrospective cohort study on Salmonella-associated diseases (SADs) was conducted in 14 public hospitals across Lagos State, Nigeria, between 1999 and 2008. METHODOLOGY: Medical records of clinically diagnosed patients with confirmed Salmonella infections were reviewed for the 10-year period. Laboratory diagnosis of typhoid fever cases in all the hospitals were first based on Widal agglutination tests then followed by culture, while non-typhoidal Salmonella infections were based on culture technique. RESULTS: A total of 85,187 confirmed cases of SADs were found, of which 880 deaths were recorded (case-fatality rate = 1.03% / 10 years). The mean incidence of SADs in Lagos State for the 10-year period was estimated at 45 cases per 100,000 persons/year, while that of typhoid fever alone was 16 cases per 100,000 persons/year. During the studied period, the number of deaths due to typhoid fever was significantly (P < 0.05) higher than deaths due to gastroenteritis except in 2003 and 2004. Risk associated with typhoidal deaths was 4 to 11 times greater when compared to gastroenteritis deaths between 2000 and 2002. Salmonella-associated diseases were most prevalent in adults 21 to 30 years of age (49.49%). Cases of patients with invasive Salmonella-associated gastroenteritis were observed mainly in children under five years of age. CONCLUSION: The current surveillance data indicated high incidence of SADs in areas exposed to environmental contaminations. This study revealed that infections caused by Salmonella enterica serovars are endemic in our environment thus poses a serious threat to public health. Constant public health education is essential to avert undue epidemics.

Cholera epidemiology in Nigeria: an overview.

Cholera is an acute diarrhoeal infection caused by ingestion of food or water contaminated with the bacterium, Vibrio cholera. Choleragenic V. cholera O1 and O139 are the only causative agents of the disease. The two most distinguishing epidemiologic features of the disease are its tendency to appear in explosive outbreaks and its predisposition to causing pandemics that may progressively affect many countries and spread into continents. Despite efforts to control cholera, the disease continues to occur as a major public health problem in many developing countries. Numerous studies over more than a century have made advances in the understanding of the disease and ways of treating patients, but the mechanism of emergence of new epidemic strains, and the ecosystem supporting regular epidemics, remain challenging to epidemiologists. In Nigeria, since the first appearance of epidemic cholera in 1972, intermittent outbreaks have been occurring. The later part of 2010 was marked with severe outbreak which started from the northern part of Nigeria, spreading to the other parts and involving approximately 3,000 cases and 781 deaths. Sporadic cases have also been reported. Although epidemiologic surveillance constitutes an important component of the public health response, publicly available surveillance data from Nigeria have been relatively limited to date. Based on existing relevant scientific literature on features of cholera, this paper presents a synopsis of cholera epidemiology emphasising the situation in Nigeria.