MOLECULAR DETECTION OF MEASLES VIRUS FROM CHILDREN DURING A SPORADIC OUTBREAK IN TWO SEMI-URBAN AREAS IN NIGERIA

Background: According to the World Health Organization (WHO), African region accounts for 36% of deaths caused by measles worldwide. Nigeria has, over the years, recorded the highest average annual measles incidence per 100,000 populations in Africa. Measles epidemics have consistently been reported in northern Nigeria, but not in the South; reports of reduced protective haemagglutination inhibition antibody titers among children in Ibadan, southern Nigeria was made. Investigation of the viral agent responsible for the disease outbreak among children presenting with rash in two semi urban areas in southern Nigeria was carried out to confirm the etiology of the disease. Methodology: Twenty six throat swabs (TS), and nineteen urine samples were collected from twenty six children residing in Onireke and Sabo areas of Ibadan following the report of an outbreak of rashes among children. Active case finding with the support of community leaders was used to locate the affected children. Multiplex reverse transcriptase polymerase chain reaction (MRT-PCR), was used to identify the agent. Results: 21 of the 26 children screened tested positive for measles virus, but none was positive for Rubella virus. There was significant association between measles infection, and households with higher number of persons. Conclusion: Mass measles vaccination that targets overcrowded, rural and inaccessible areas is needed to increase herd immunity. Public health enlightenment on the benefits of vaccination is encouraged

Seasonal abundance and molecular identification of West Nile virus vectors, Culex pipens and Culex quinquefasciatus (diptera: culicidae) in Abeokuta, South-West, Nigeria

Background: West Nile virus (WNV) infection, is an arbovirus infection with high morbidity and mortality, the vector responsible for both human and animal transmission is Culex pipens complex.Objective: To determine the species distribution and seasonal abundance of Culex pipens and Culex quinquefasciatus mosquitoes in Abeokuta, Nigeria.Methods: Mosquitoes belonging to the Culex pipens complex were captured in three different locations located within Abeokuta Metropolis between March 2012 and January 2013. Individual species were identified using morphometric methods. Amplification of the Ace2 gene by PCR confirmed morphormetric identification of the mosquitoes.Results: A total of 751 mosquitoes were captured. Culex quinquefaciatus recorded the highest distribution of vectors with 56.6% and Culex pipens 43.4% (P > 0.05). Idi aba community recorded the highest distribution of mosquito vectors with 42.9% (n=322) and Culex quinqueaciatus was more abundantly distributed with 183 mosquitoes. Aro community recorded 32% (n=240) of captured mosquitoes with Culex quinquefaciatus having a higher level of abundance and lastly Kemta with a distribution of 25.1% (n=189).Conclusion: Results from this study show that potential vectors of WNV abound within Abeokuta, putting residents at high risk of West Nile infection. We advocate for introduction of routine testing of WNV in Abeokuta and Nigeria.Keywords: West Nile Virus, Culex pipens complex, PCR, Abeokut

Surveillance of acute flaccid paralysis in Akwa Ibom State, Nigeria 2004–2009

Introduction: The last case of wild polio virus transmission occurred in Akwa Ibom state in October 2001; however, combination high routine immunization coverage with OPV, high quality AFP surveillance, mass immunization campaign in which two doses of potent oral polio vaccine is administered to eligible children and mop-up campaigns in areas with identified immunization or surveillance gaps has help the state in maintaining a free polio status for over ten years. This study was carried out to describe the characteristics of reported acute flaccid paralysis cases between 2004 and 2009, and to evaluate the performance of the acute flaccid paralysis surveillance system using indicators recommended by the World Health Organization. Methods: A retrospective study was conducted among children, 0-15 years, by the World Health Organization (WHO) and Epidemiology unit of State Ministry of Health (SMOH), Uyo. The demographic characteristics and the results of isolation and identification of polio and other enteroviruses in stool samples sent to the WHO Polio Laboratory Ibadan for cases was analyzed. Results: A total of 521 cases of AFP (270 males and 251 females) aged 0 month to = 15 years were reported by the surveillance system between 2004 and 2009. Those below 5 years of age accounted for 82.5% of cases reported and investigated. Of the 521 cases investigated 512 (98.3%) received at least three doses of oral polio vaccine, while 9(1.7) never received any oral polio vaccine (zero-dose). In all 5.1% of the isolates were Sabin, 7.9% non polio enterovirus (NPEV) and 2.3% were classified by national expert committee as compatible with poliomyelitis. There was consistent and steady increase in three critical indicators; Non polio AFP rate in children <15 years from 4.5 to 6.4 per 100 000 population, proportion of AFP cases with 2 stool specimens collected within 14 days of onset of paralysis from 57% in 2005 to 91% in 2009 and proportion of Local Government Areas (Districts) meeting both core indicators from 23% in 2005 to 87% in 2009. The highest numbers of cases were seen in the months of March, May and September. Conclusion: This study showed high levels of surveillance performance with some challenges in reverse the cold chain system, the continuation and sustained AFP case detection, prompt investigation and response, improvement in the reserve cold chain system would achieve optimal standards recommended by WHO and might provide a good model for the eradication of poliomyelitis.Key words: Acute flaccid paralysis, Surveillance, Poliomyelitis, Nigeri

Seasonal abundance and molecular identification of West Nile virus vectors, Culex pipens and Culex quinquefasciatus (diptera: culicidae) in Abeokuta, South-West, Nigeria.

Background: West Nile virus (WNV) infection, is an arbovirus infection with high morbidity and mortality, the vector responsible for both human and animal transmission is Culex pipens complex. Objective: To determine the species distribution and seasonal abundance of Culex pipens and Culex quinquefasciatus mosquitoes in Abeokuta, Nigeria. Methods: Mosquitoes belonging to the Culex pipens complex were captured in three different locations located within Abeokuta Metropolis between March 2012 and January 2013. Individual species were identified using morphometric methods. Amplification of the Ace2 gene by PCR confirmed morphormetric identification of the mosquitoes. Results: A total of 751 mosquitoes were captured. Culex quinquefaciatus recorded the highest distribution of vectors with 56.6% and Culex pipens 43.4% (P > 0.05). Idi aba community recorded the highest distribution of mosquito vectors with 42.9% (n=322) and Culex quinqueaciatus was more abundantly distributed with 183 mosquitoes. Aro community recorded 32% (n=240) of captured mosquitoes with Culex quinquefaciatus having a higher level of abundance and lastly Kemta with a distribution of 25.1% (n=189). Conclusion: Results from this study show that potential vectors of WNV abound within Abeokuta, putting residents at high risk of West Nile infection. We advocate for introduction of routine testing of WNV in Abeokuta and Nigeria. Keywords

IMMUNITY TO POLIOVIRUS SEROTYPES IN CHILDREN POPULATION OF SELECTED COMMUNITIES IN SOUTH-WEST, NIGERIA

Background: Poliovirus outbreaks are still reported in Nigeria despite renewed efforts to improve vaccine coverage, thus suggesting the existence of susceptible hosts. Also, there is anecdotal evidence of variation in vaccine coverage by region and specifically between urban and rural communities. Consequently, this study assessed neutralizing antibodies to poliovirus serotypes among children in selected urban and rural communities in south western Nigeria. Methodology: Two hundred and forty-four {(M=119, F=125); Urban: 142 (M=63, F=79); Rural: 102 (M=56, F=46)} children of consenting parent/guardian aged one week to 15 years were enrolled for the study. About 2-3ml of blood was collected from each child by venepuncture into a labelled sterile container free of anticoagulants. Subsequently, questionnaire was administered to the parent/guardian of each child to retrieve relevant information. Recovered sera were analysed for detectable neutralizing antibodies to poliovirus serotypes by the standard method of constant virus, varying serum dilutions. Results: Overall, 64.3% (n=157) of the children had detectable neutralizing antibodies to the three poliovirus serotypes. Also, 84.8% (n=207), 91.0% (n=222) and 75.0% (n=183) of the children had detectable antibodies to poliovirus serotypes 1, 2 and 3 respectively. Eighty seven (35.7%) of the children had no detectable neutralizing antibody to at least one of the three poliovirus serotypes, while 9 (3.7%) children had no detectable neutralizing antibody to the three poliovirus serotypes. Geometric mean titre (GMT) of neutralizing antibodies to the three poliovirus serotypes varied significantly (p=0.0005). Conclusion: Disparity in immunity to poliovirus infection and existence of children with low or zero neutralizing antibody levels were confirmed

Some genetic characteristics of sabin-like poliovirus isolated from acute flaccid paralysis cases in Nigeria

A total of 34 sabin strains of the poliovirus isolated from 22 children with 60-day follow-up residual acute flaccid paralysis (AFP) were genetically characterized and screened for any form of recombination. Sequence analysis of the 906-nucleotide capsid showed that all the isolates were similar to their original sabin serotypes, however two of the viruses had drifted in their 3D noncapsid regions toward a sabin-sabin and sabin-nonpolio entero combination. Routine immunization in Nigeria is low and in spite of the increase in the frequency of supplemental immunizations, a lot of children are still inadequately immunized, which may be the reason for our observation in this study. Although we are not dealing with a case of circulating vaccine derived poliovirus (cVDPV) yet, if the above condition persists, the advent of cVDVP may not be too far. There is therefore the need to maintain a high quality mass immunization and sustained routine immunization. Key words: Poliovirus, sequence, crossover, non polio enterovirus, recombination, genome, Sabin-like, vaccine, Nigeria. African Journal of Biotechnology Vol.2(11) 2003: 460-46

Epidemiology of Rotavirus A in Nigeria: Molecular Diversity and Current Insights

Rotavirus induced acute gastroenteritis AGE has been a major disease burden in Nigeria, since it was first reported in 1985. Prevalence rates have increased with severe public health consequences particularly among children. The vaccine Rotarix® has been introduced and is commercially available in Nigeria. However routine rotavirus vaccination is yet to be introduced into the National Immunization Program. Molecular epidemiology of rotavirus in Nigeria has shown the presence of various genotypes, with genotype G12P[8] being the most recent introduction. There are however gaps in molecular data on rotavirus in Nigeria. We therefore reviewed molecular data on rotavirus isolated in Nigeria and also analyzed VP4 and VP7 genes of Nigerian rotavirus strains in Genbank. We have shown that there is a distinct trend in rotavirus molecular epidemiology in Nigeria, with new genotype introductions occurring after the year 2010. We also observed from our analysis the emergence of genotype G12 Lineage III as a dominant genotype. This information elucidates rotavirus molecular epidemiology in Nigeria and gives insight to the expanding landscape of rotavirus genotypes. We recommend the institution of molecular surveillance country wide, before considering the inclusion of rotavirus vaccination into the National Immunization Program in Nigeria, in other to monitor evolution of divergent or recombinant strains