Characterization of Foot-and-Mouth Disease Viruses Collected in Nigeria Between 2007 and 2014: Evidence for Epidemiological Links Between West and East Africa.

This study describes the molecular characterization of 47 foot-and-mouth disease (FMD) viruses recovered from field outbreaks in Nigeria between 2007 and 2014. Antigen ELISA of viral isolates was used to identify FMD virus serotypes O, A and SAT 2. Phylogenetic analyses of VP1 nucleotide sequences provide evidence for the presence of multiple sublineages of serotype SAT 2, and O/EAST AFRICA 3 (EA-3) and O/WEST AFRICA topotypes in the country. In contrast, for serotype A, a single monophyletic cluster of viruses has persisted within Nigeria (2009-2013). These results demonstrate the close genetic relatedness of viruses in Nigeria to those from other African countries, including the first formal characterization of serotype O/EA-3 viruses in Nigeria. The introductions and persistence of certain viral lineages in Nigeria may reflect transmission patterns via nomadic pastoralism and animal trade. Continuous monitoring of field outbreaks is necessary to dissect the complexity of FMD epidemiology in sub-Saharan Africa.

Detection of human rotavirus in faeces from diarrhoeic calves in north-east Nigeria.

Information on the epidemiology of rotavirus in any particular area is necessary for vaccine development against the disease caused by the virus. This study presents preliminary information on the prevalence of human rotavirus in diarrhoeic calves in North-east Nigeria. Faecal samples from 188 diarrhoeic calves in various farms in North-east Nigeria, obtained between November 1998 and February 1999, were analysed by ELISA for the presence of rotaviruses. A prevalence rate of 3.2% was recorded, with the virus being prevalent among calves aged 29-56 days (p < 0.05). The implications of these findings are discussed with respect to the close association between the herdsmen and their animals and the sharing of a common source of drinking water in the predominantly livestock-producing communities of North-east Nigeria.

Molecular epidemiology of rotaviruses in Nigeria: detection of unusual strains with G2P[6] and G8P[1] specificities.

During an epidemiological study on rotaviruses among diarrheic children in the northeastern and middle belt regions of Nigeria, the distribution of G and P types was investigated in 127 stool specimens. By PCR G typing, the G type of rotaviruses in 97 samples was identified. Interestingly, an unusual G8 type, as well as common G1, G2, and G3 types, was detected more frequently (31 of 112; 27.7%). Eleven samples contained multiple G types, and a G9 strain (Bulumkutu) was identified for one of the probable mixed infections. In PCR P typing, P[6] was detected most frequently, P[8] being the second most common type, while the P type of 73 samples could not be identified. One rotavirus strain with a G8 type specificity could be cultivated in cell culture, and the P type of this strain was found to be P[1], which is usually carried by bovine strains. When the combinations of G and P types were examined, the unusual strains G2P[6] and G8P[1] were often identified. Sequence analysis was performed for the VP7 gene of the G9 strain Bulumkutu and the VP4 and VP7 genes of G8P[1] strain HMG035. The VP7 sequence of the Nigerian serotype G9 was more closely related to that of a Brazilian strain than to those of other African strains. The VP7 and VP4 genes of G8P[1] strain HMG035 were found to be very similar to that of a Thai bovine strain A5, suggesting that bovine strains may have been transmitted directly to humans. These results highlight an unexpected diversity among rotavirus strains in Nigeria and emphasize the need for further serological and genetic surveys on more rotavirus strains in African countries, including Nigeria.

Further characterization of field strains of rotavirus from Nigeria VP4 genotype P6 most frequently identified among symptomatically infected children.

Polymerase chain reaction was utilized to characterize the VP4 types of 39 Rotavirus field isolates from symptomatically infected children in Nigeria. Genotype P6 was identified most frequently, occurring in 41.03 per cent of the typed specimens. Genotype P8 was identified as the next most prevalent (33.3% per cent). Genotype p6 was widespread (68.75 per cent) among infected neonates in Southern Nigeria, but mix infection was more prevalent (70 per cent) among Northern Nigerian children. Four distinct strains were identified with four different P genotypes. Overall strain G1P8 predominated (22.22 per cent) followed by G3P6 (17.8 per cent). Strain G1P8 was most prevalent (70 per cent) among infants aged 3.1-9 months, but strain G3P6 was most frequently identified among neonates < or = 3 months (50 per cent). While strain G1P8 was circulating across the country at this time, strain G3P6 was regionally most identified (77.8 per cent) in Southern Nigeria. The presence of untypeable VP4 gene in Nigeria was demonstrated. The occurance of mix infection genotype demonstrates the potential for reassortment events among different rotavirus genogroups in Nigeria. The epidemiological implications of these findings for rotavirus vaccine development and application in the country were discussed.

Serotype of Nigerian rotavirus strains.

Three hundred and fourteen stool samples collected from children < 5 years between December 1993 and August 1995 were analysed by PAGE, ELISA, PCR and Dot-blot hybridization technique for electropherotype and serotype distribution of rotavirus infection among Nigerian paediatric patients. 14.3% of the children were positive for rotavirus antigen. Children aged 6-9 months were most often infected, accounting for 35.6% of all positive samples, 91.1% of rotavirus-positive samples could be serotyped. Serotypes G2, G4 and G8 were not detected. Serotype G3 predominated (62.5%) in southern Nigeria, while mixed infection specificity was more widespread (63.6%) in northern Nigeria. The presence of some untypeable samples may indicate serotypes which the serotype-specific primers and cDNA probes used could not detect. Electropherotypes of 26 (57.7%) of the positive samples were determined. Two and 3 migration patterns were observed among the short and long-pattern electropherotypes, respectively. Implications for vaccine development and utilization in the country are discussed.

Nigerian rotavirus serotype G8 could not be typed by PCR due to nucleotide mutation at the 3' end of the primer binding site.

A rotavirus strain HMG89 from Nigeria with short electrophoretic pattern was typed G3 by PCR. A cDNA clone from the PCR product which hybridised in Northern blots to RNA segment 9 of the homologous Nigerian rotavirus strain HMG89 and laboratory reference strain 69M but not to other mammalian group A rotaviruses was sequenced. The VP7 gene 9 sequence is 1060 nucleotides long with two base deletions at positions 1034-1035. Sequence analysis of the primer (aAT8) used in the previous PCR serotyping assay revealed a mutation in one of the three nucleotide bases at the 3' end of the primer binding site accounting for our inability to serotype G8 strains in our samples. These findings demonstrate that PCR analysis can, albeit infrequently, lead to error in typing of rotaviruses due to small numbers of mutations in the primer binding region.

Sequence analysis of VP7 gene of two Nigerian rotavirus strains.

The complete nucleotide sequences of gene 9 (VP7) of rotavirus strains MGH66 and RHIB55 isolated in northern and southern Nigeria, respectively, were determined. The sequence of either strain was 1062 nucleotides along with two potential glycosylation sites and two in-phase initiation codons encoding a protein of 326 amino acids provided the first ATG codon was utilised. Comparison of the deduced amino acid sequences of VP7 of the strains with that of published sequences of serotype G1 strains and a representative strain of each of serotypes 2-6 and 8-14 revealed > or = 91.41% and > or = 81.60% homology, respectively. The stool sample obtained from a diarrhoeic child in Maiduguri containing strain MGH66 was classified by polymerase chain reaction (PCR) technique as possessing a dual infection specificity of VP7 serotypes G1 and G3. The nucleotide sequencing, however, revealed the dual infection specificity of VP7 serotypes G1 and G8. The implications of nucleotide sequence analysis for serotyping of rotavirus strains originating from different geographical regions and for vaccine development are discussed.

Susceptibility of Nigerian west African dwarf and red Sokoto goats to a strain of Trypanosoma congolense.

West African Dwarf (WAD) and Red Sokoto (RS) goats were experimentally infected with the Kafanchan strain of Trypanosoma congolense and the course of the infection was monitored. The organism was pathogenic and produced fatal disease in the goats, which was characterized by rapid progressive anaemia, leucocytosis, weight loss and death. All RS goats died within 11 days of infection, and had a mean reduction in packed cell volume (PCV) of 11%. In West African Dwarf goats, one death occurred on Day 13 post-infection with a mean drop in PCV of 9%. Statistically significant (P < 0.05) mean reductions in values of PCV, haemoglobin and red blood cell counts were observed between the infected and control animals of both breeds, and also between the infected WAD and infected RS goats. The anaemia produced was macrocytic. Leucocytosis characterized by neutropenia and lymphocytosis was observed among infected WAD goats, but leucopenia characterized by neutrophilia and lymphopenia was observed in infected RS goats. Infected WAD goats recorded some positive unit weight gain in spite of the infection. It was concluded that the RS breed of goats is more susceptible to T. congolense infection than the WAD breed.

Changes in levels of transaminases in goats experimentally infected with Trypanosoma congolense.

Goats were experimentally infected with Trypanosoma congolense and then treated with Berenil after 9 days of infection. The infection produced increases in glutamate oxalacetate transaminase (GOT) and glutamate pyruvic transaminase (GPT) values. Mean GOT values in infected West African dwarf goats were generally lower than in infected Red Sokoto goats. Treatment with Berenil did not produce any significant effect on their levels probably because of the relapse infection recorded in this study.