Search

Canine parvovirus (CPV) is a contagious and highly pathogenic virus of dogs. After its first report in 1978, the CPV original type (CPV-2) was rapidly and totally replaced by three antigenic variants named CPV-2a, CPV-2b and CPV-2c that circulate in various countries at different frequencies and recently reported in Nigeria. This study describes the molecular characterization of 28 CPV strains in dogs presenting with gastroenteritis in veterinary clinics at Lagos and Ibadan, Nigeria. The results show the predominance (92.8%) of CPV-2a, while CPV-2c was found only in two samples. Phylogenetic analyses revealed that the CPV Nigerian strains were closely related to Asian strains and 26 CPV-2a out of 28 CPV sequences fell into 2 different subclades consistent with predicted amino acid mutations at position 267, 321, 324 and 440. Lys321Asn was evident in all the Nigerian strains whilst Phe267Tyr and Tyr324Ile were observed in 96.4% of the sequences, respectively. Thr440Ala occurred in 89.3% of sequences from this study. The new CPV-2a was predominant and appears to have replaced other CPV-2a strains in South-western Nigeria whilst the CPV-2c strain which is identical to the isolate recently reported in Northern Nigeria, may have been introduced in this country at the time of this study. Monitoring virus epidemiology is important to better understand the dynamics of CPV evolution and the eventual need to change or improve existing vaccination strategies.

ABSTRACTA total of 2,570 apparently healthy human immunodeficiency virus-negative adults from the six geopolitical zones in the country were enrolled in our study in 2006. The samples were assayed using the Cyflow technique. Data were analyzed using the Statistical Package for Social Scientists (SPSS). The majority (64%) of the participants had CD4 counts within the range of 501 to 1,000 cells/µl. The reference range for CD4 was 365 to 1,571 cells/µl, while the reference range for CD8 was 145 to 884 cells/µl.

In May 1988, the World Health Assembly resolved to eradicate poliomyelitis globally by the year 2000. Despite the reported success in national immunization days, acute flaccid paralysis surveillance and accelerated efforts to meet the deadline including ‘mopping-up’ were executed in 1999 and subsequent years. Nigeria remains one of the major reservoirs for wild poliovirus transmission. Neutralizing antibody titre to the three poliovirus serotypes was determined among children from different communities in southwest of Nigeria, and analysed by age, gender and location. About 0.5–2 ml of blood sample was collected by venepuncture from each child. Aliquot of serum from each blood sample was inactivated prior to neutralization test by the beta method for poliovirus antibodies. A total of 347 (59.6 per cent) out of 500 and 82 children enrolled for the study had at least antibody titre of 1:8 against each of the three poliovirus serotypes. Immunity level to the three poliovirus serotypes increased with age and peaked in children aged 4–6 years. Seven (53.8 per cent) out of 13 unvaccinated children tested in the study had detectable neutralizing antibody to the three serotypes. Immunity pattern of P2 > P1 and P3 was observed but no correlation between gender and antibody to the poliovirus serotypes. The populations had 59.6 per cent herd immunity for the three poliovirus serotypes. In a country with high incidence of poliomyelitis this situation leaves a high number of non-immunized children at the risk of infection with one or more poliovirus serotypes.

A community-based survey to determine the prevalence of human T-cell lymphotropic type I (HTLV-I) and type II (HTLV-II) virus infections in mothers and children in south-western Nigeria was carried out using blood samples collected in 1993. A multistage cluster, random sampling procedure was used to select 460 mother-child pairs (476 children because there were 16 sets of twins) from 14 enumeration areas. A commercially available, whole HTLV-I lysate antigen-based ELISA method was used to screen for HTLV-I and HTLV-II antibodies in the samples. A synthetic peptide antigen-based ELISA was then used to differentiate between antibody reactivity to either HTLV-I or HTLV-II. Reactivity to HTLV-I or HTLV-II antibodies was found in 4.3 per cent (20/460) of mothers and in 1.1 per cent (5/476) of children in both rural and urban communities and all the positive children were males. None of the 16 sets of twins in this study was positive for either HTLV-I or HTLV-II. Also none of the mother-child paired sera tested showed concordance for either HTLV-I or HTLV-II antibody positivity. The lack of concordance between mother and child sera suggests that vertical transmission may not be the major route of transmission of HTLV infection to children in south-western Nigeria. Other modes of transmission, such as the re-use of unsterilized needles for injections and surgical knives in local scarification, which are common practices in the region, need to be investigated as they may prove to be more important than vertical transmission. These findings have important implications for any control programme for diseases that can be spread by the same routes as HTLV infection (the human immunodeficiency viruses, hepatitis B, and hepatitis C infections).

This study compared the immune responses of healthy children to one or two doses of Oka/Merck varicella vaccine. Both cell-mediated and humoral immune responses were significantly stronger 1 year later among children given two doses 3 months apart than among those given a single dose. Long-term follow-up studies are needed to determine whether two doses of vaccine indeed provide more complete and more durable protection than a single dose against breakthrough varicella in healthy children.