Characterization of Vibrio cholerae Strains Isolated from the Nigerian Cholera Outbreak in 2010.

We examined clinical samples from Nigerian patients with acute watery diarrhea for Vibrio cholerae during the 2010 cholera outbreak. A total of 109 suspected isolates were characterized, but only 57 V. cholerae strains could be confirmed using multiplex real-time PCR as well as rpoB sequencing and typed as V. cholerae O:1 Ogawa biotype El Tor. This finding highlighted the need for accurate diagnosis of cholera in epidemic countries to implement life-saving interventions.

Molecular characterization of the circulating strains of Vibrio cholerae during 2010 cholera outbreak in Nigeria.

This study aimed at characterizing the phenotypic and toxigenic status of circulating strains of cholera during outbreaks in Nigeria, employing molecular typing techniques. Two hundred and one samples of rectal swabs, stool, vomitus, water (from the well, borehole, sachet, stream, and tap) and disinfectants (sodium hypochlorite) were collected from three states in the country. The samples were inoculated on thiosulphate-citrate bile salt-sucrose (TCBS), Cary-Blair transport medium and smeared on glass slides for direct examination. The Vibrio cholerae isolates were serotyped, biotyped, and characterized using PCR of the cytotoxin gene A (ctxA), wbeO1, and wbfO139 gene primer. Of the 201 samples screened, 96 were positive for V cholerae O1 (48%), with 69 (72%) positive for ctxA gene. The results from this study showed that the circulating strains of cholera in Nigeria were of Ogawa serotype, also observed in other outbreaks in Nigeria (1991, 1992, and 1996). However, the strains were of the Classical biotype and were mainly (72%) ctxA gene-positive. This current investigation has confirmed the production of cholera toxin by the circulating strains, and this could be harnessed for possible cholera vaccine production in Nigeria.

An assessment of the emergency response among health workers involved in the 2010 cholera outbreak in northern Nigeria.

BACKGROUND: The 2010 cholera outbreak in northern Nigeria affected over 40,000 people, with a case fatality rate (CFR) of ≥3.75%. We assessed the emergency response of health care workers (HCWs) involved in case management. METHOD: This was a cross-sectional study with data collected through a self-administered questionnaire. Data entry and analysis were performed using Epi info software. RESULTS: A total of 56 HCWs were interviewed. The mean age was 31 years (SD±8.16 years). The majority of the HCWs (80%; n=45) were aged 18-39 years. Most were community health extension workers (60%), and 3.6% (n=2) were medical doctors. Many of the HCWs had less than 2 years of work experience (42%). Additionally, 82% of the respondents had <1 week of cholera emergency response training, and 50% of the HCWs managed >20 suspected cases of cholera per day. Although 78% of HCWs reported the practice of universal safety precautions, 32% (n=18) knew HCWs who developed symptoms of cholera during the epidemic, most of which was believed to be hospital acquired (78%). We also found that 77% (n=43) of HCWs had no access to the required emergency response supplies. CONCLUSION: Inadequate training, a lack of qualified HCWs and a limited supply of emergency response kits were reported. Therefore, the government and stakeholders should address the gaps noted to adequately control and prevent future epidemics.

Application of a point-of-care test for the serodiagnosis of typhoid fever in Nigeria and the need for improved diagnostics.

INTRODUCTION: There is an urgent need for affordable point-of-care diagnostics for the differentiation of febrile illnesses and the confirmation of typhoid in endemic countries. METHODOLOGY: Blood samples were collected from febrile patients with clinical suspicion of typhoid and screened for typhoid fever using the Widal and Typhi Dri Dot tests, while stool and blood samples were screened for Salmonella Typhi using the culture method as well as PCR as a confirmatory test. RESULTS: A high proportion of febrile patients from Lagos with clinical suspicion of typhoid fever reacted positively in a simple and rapid latex agglutination assay for typhoid fever, indicating that this illness is a common and presumably under-diagnosed health problem in this metropolis. Seropositivity was 19.2% in the rapid test compared with 22.9% in the classical Widal test. The confirmation of typhoid in these seropositive patients appeared cumbersome because of negative blood cultures and low DNA yield in molecular testing. A review of the literature revealed that in Nigeria seroprevalence rates can be high in the normal population and that pathogens other than S. Typhi are often isolated from the blood of seropositive febrile patients. CONCLUSION: The simplicity and the relatively high specificity (97.8%) of the rapid test as determined in a study performed in Indonesia calls for a further validation of this promising test for use in Africa.