Biology subjects

Ibok, U. I.

Publications and source records attributed to Ibok, U. I..

4 recordsLinked to original sources

bioRxiv2017

Development of Echovirus 29 cytopathology in RD cell line might not happen within 10 days post inoculation.

Echovirus 29 (E29) is a member of Species Enterovirus B (EV-B) in the genus Enterovirus, family Picornaviridae, order Picornavirinae. In Nigeria, molecular characterization of E29 was first described in 2002. In 2015, we found that a new clade of E29 had replaced that described in Nigeria in 2002-2003. To date, E29 isolates described from Nigeria were isolated in cultures of RD cell line. In 2016, we characterised an E29 strain that did not show cytopathology on RD cell line within the recommended 10 days of culture.\n\nHere we show that the E29 in question grows with evident CPE in RD cell culture like other members of the clade when allowed to stay in culture for 13 to 14 days. The findings of this study therefore suggest that some of the samples declared negative for enteroviruses by the current WHO cell culture based detection algorithm might be false negatives. It is therefore encouraged that those particularly interested in non-polio enteroviruses endeavour to maintain at least 14 days incubation in cell culture in a bid to accommodate NPEVs like E29 that might need longer time to develop CPE especially when present at low titre.

microbiology↗

bioRxiv2017

Nonpolio enteroviruses can also be recovered from non-reproducible cytopathology in L20B cell line.

Samples showing cytopathology (CPE) on initial inoculation into L20B cell line but with no observed or reproducible CPE on passage in L20B or RD are considered negative for both poliovirus and nonpolio enteroviruses (NPEVs). The phenomenon is termed non-reproducible CPE. Its occurrence is usually ascribed to the likely presence of reoviruses, adenoviruses and other non-enteroviruses. This study aimed to investigate the likelihood that NPEVs are also present in cases with non-reproducible CPE.\n\nTwenty-six (26) cell culture suspensions were analyzed in this study. The suspensions were collected from the WHO National Polio Laboratory, Department of Virology, College of Medicine, University of Ibadan. The suspensions emanated from 13 L20B cell culture tubes that showed cytopathology within 5 days of inoculation with fecal suspension from AFP cases. However, on passage into one each of RD and L20B cell lines, the CPE was not reproducible. All samples were subjected to RNA extraction, cDNA synthesis, the WHO recommended VP1 RT-seminestedPCR assay, species resolution PCR assay, sequencing and phylogenetic analysis.\n\nSix (6) samples were positive for the VP1 RT-seminested PCR assay. Only four of which were positive by the species resolution PCR assay. The four amplicons were sequenced, however, only three (3) were successfully identified as Coxsackievirus A20 (2 isolates) and Echovirus 29 (1 isolate).\n\nThe results of this study unambiguously showed the presence of NPEVs (particularly CVA20 and E29) in cell culture supernatants of samples with CPE on initial inoculation into L20B cell line but with no observed or reproducible CPE on passage in RD cell line. Therefore, like reoviruses, adenoviruses and other non-enteroviruses, NPEVs can also be recovered in cases with non-reproducible CPE.

microbiology↗

bioRxiv2017

Preponderance of Enterovirus Species C in RD-L20B Cell Culture Negative Stool Samples from Children Diagnosed with Acute Flaccid Paralysis in Nigeria.

AbstractsRecently, a reverse transcriptase seminested polymerase chain reaction (RT-snPCR) assay was recommended by the WHO for direct detection of enteroviruses from clinical specimen. In this study, we use the assay and its modification to screen acute flaccid paralysis (AFP) samples previously confirmed negative for enteroviruses by the RD-L20B algorithm.\n\nThirty paired stool suspensions collected in 2015 as part of the national AFP surveillance program in different states of Nigeria were analyzed in this study. The samples were previously confirmed negative for enteroviruses by the polio laboratory in accordance with the WHO recommended RD-L20B cell culture based algorithm. Two samples previously confirmed to contain enteroviruses were included as positive controls. All samples were subjected to RNA extraction, and the RT-snPCR assay and its modifications. All amplicons were sequenced and enteroviruses identified using the enterovirus genotyping tool.\n\nOverall, amplicons were recovered from the two controls and 50% (15/30) of samples screened. Fourteen were successfully typed of which, 7.1% (1/14), 21.4% (3/14), 64.3% (9/14) and 7.1% (1/14) were EV-A, EV-B, EV-C and a mixture of EV-B and C (EV-C99 and E25), respectively. The two controls were identified as EV-C99 and CV-A1, both EV-Cs. The PV-2 detected had VP1 ILE143. Hence, a vaccine strain.\n\nThe results of this study showed that about 50% of enterovirus infections (including some Sabin PV2s) are being missed by the RD-L20B cell culture based algorithm. This highlights the value of the RT-snPCR assay and its modifications. The circulation and preponderance of EV-Cs in Nigeria was also confirmed.

microbiology↗

bioRxiv2016

Enterovirus A119 in a child with Acute Flaccid Paralysis, Nigeria

The oldest EV-A119 record was in 2008 in a chimpanzee in Cameroon and subsequently in more non-human primates and healthy children. Here we report for the first time the detection of EV-A119 in a child with Acute Flaccid Paralysis, thus suggesting possible association with a clinical condition in humans.

epidemiology↗