Molecular characterization & recombination analysis of complete enterovirus-88 isolated from acute flaccid paralysis cases in India

Background & objectives

Focus on non-polio enteroviruses (NPEVs) causing acute flaccid paralysis (AFP) due to myelitis has increased with the containment of the poliovirus. Enterovirus-B88 (EV-B88) has been associated with the AFP cases in Bangladesh, Ghana, South Africa, Thailand and India. In India, EV-B88 infection was linked to AFP a decade ago; however, to date, no complete genome has been made available. In this study, the complete genome sequence of EV-B88 was identified and reported from two different States (Bihar and Uttar Pradesh) in India using the next-generation sequencing technique.

Methods

Virus isolation was performed on the three AFP suspected cases as per the WHO-recommended protocol. Samples showing cytopathic effects in the human Rhabdocarcinoma were labelled as NPEVs. Next-generation sequencing was performed on these NPEVs to identify the aetiological agent. The contiguous sequences (contigs) generated were identified, and reference-based mapping was performed.

Results

EV-B88 sequences retrieved in our study were found to be 83 per cent similar to the EV-B88 isolate from Bangladesh in 2001 (strain: BAN01-10398; Accession number: AY843306.1). Recombination analyses of these samples demonstrate recombination events with sequences from echovirus-18 and echovirus-30.

Interpretation & conclusions

Recombination events in the EV-B serotypes are known, and this work reconfirms the same for EV-B88 isolates also. This study is a step in increasing the awareness about EV-B88 in India and emphasizes future studies to be conducted in the identification of other types of EV present in India.

Utilization and Assessment of Throat Swab and Urine Specimens for Diagnosis of Chikungunya Virus Infection

Chikungunya is a mosquito-borne infection with clinical presentation of fever, arthralgia, and rash. The etiological agent Chikungunya virus (CHIKV) is generally transmitted from primates to humans through the bites of infected Aedes aegypti and Aedes albopictus mosquitoes. Outbreaks of Chikungunya occur commonly with varied morbidity, mortality, and sequele according to the epidemiological, ecological, seasonal, and geographical impact. Investigations are required to be conducted as a part of the public health service to understand and report the suspected cases as confirmed by laboratory diagnosis. Holistic sampling at a time of different types would be useful for laboratory testing, result conclusion, and reporting in a valid way. The use of serum samples for virus detection, virus isolation, and serology is routinely practiced, but sometimes serum samples from pediatric and other cases may not be easily available. In such a situation, easily available throat swabs and urine samples could be useful. It is already well reported for measles, rubella, and mumps diseases to have the virus diagnosis from throat swabs and urine. Here, we present the protocols for diagnosis of CHIKV using throat swab and urine specimens.

Non-polio Enteroviruses in Karnataka, India: Virological surveillance of acute flaccid paralysis cases (July 1997-2013)

BACKGROUND AND OBJECTIVES

Since 1997 National Institute of Virology, Bangalore Unit involved in WHO's Acute flaccid paralysis paediatric cases surveillance programme to isolate and detect polioviruses. Stool samples yielded not only polioviruses but also Non-Polio enteroviruses. This report is an overview of non-polio Enterovirus (NPEV) epidemiology in Karnataka state, India for the period of 16-years and 6 months from July 1997-2013.

METHODS

A total of 19,410 clinical samples were processed for virus isolation as a part of acute flaccid paralysis (AFP) surveillance for Global Polio Eradication Programme in India at National Polio Laboratory, at Bengaluru. NPEV detection was performed by virus isolation on cell culture according to World Health Organisation recommended protocols.

RESULTS

A total of 4152 NPEV isolates were obtained. The NPEV isolation rate varied from year to year but with a total NPEV rate of 21.39%.

CONCLUSION

A seasonal variation was noted with high transmission period between April and October with peaks in June-July. The male to female ratio was 1:1.2. The isolation of NPEV decreased significantly with the increase in age. Epidemiology of NPEVs from AFP cases in Karnataka is described.