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. Pan African Medical Journal 2012; 12:5

The prevalence and plasmid profile of non-typhoidal salmonellosis in children less than five years in Lagos metropolis, 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

Staphylococcal bacteraemia among human immunodeficiency virus positive patients at a screening center in Lagos, Nigeria

Bacteraemia due to Staphylococcus aureus in Human immunodeficiency virus (HIV) – positive patients is associated with increased mortality rate. The present study aimed at determining the species distribution and occurrence of staphylococcal bacteraemia in HIV – positive patients in Lagos, Nigeria. Staphylococcal blood stream infection in febrile HIV patients was investigated by culture technique. The antibiotic resistance pattern was investigated using the disk diffusion and methicillin resistance was confirmed by the salt agar methods. The genetic relatedness of S. aureus was determined using Pulsed Field Gel Electrophoresis (PFGE). Eighty-six patients comprising 47 (55%) female and 39 (45%) male, median aged 34 years took part in the study. Staphylococci were identified in 16 (18.6%) patients; 13 (15.1%) and 3 (3.5%) with single and dual Staphylococcus species respectively. The isolates consisted of S. aureus (7 patients), followed by S. haemolyticus (4 patients). Of the thirteen (13) antibiotics tested, isolates were resistant to ampicillin (AMP; 89.5%), tetracycline (TET; 68.4%), cloxacillin (CXC; 89.5%), oxacillin (OXA; 68.4%); chloramphenicol (CHL; 57.9%) and trimethoprim-sulphamethoxazole (SXT; 63.1%). The overall percentage of all the isolates resistant to gentamicin, erythromycin and amoxicillin-clavulanic acid was less than 50%. All the isolates were susceptible to ciprofloxacin and vancomycin and none was positive for methicillin resistance except a strain of S. haemolyticus. Significant genetic diversity was observed among the S. aureus isolates with a predominant pulsotype A. The two isolates with pulsotype A had identical resistotype (AMP, ERY, TET, CXC, SXT). Other PFGE patterns were represented by single isolates except pulsotype C which had a subtype. In these patients, the most frequent Staphylococcus species isolated was S. aureus and the results revealed that clonal dissemination of a virulent pulsotype of S. aureus among this population is plausible and should be a cause for concern