ICEID Abstracts: Mild Respiratory Illness Caused by H5N1 and H9N2 Infections among Young Children in Dhaka, Bangladesh, 2011

2012 International Conference on Emerging Infectious Diseases
Program and Abstracts Book
pg: 160:

A. Chakraborty1,2, K. Sturm-Ramirez1,3, M. Khan1, M. Haider2, R. Sultana1, N. Ali
Rimi1, M. Islam1, A. Al Mamun1, D. Goswami1, A. Alamgir2, M. Rahman1, K. Jamil2,
A.D. Storms3, E. Azziz-Baumgartner3, K. Hancock3, B. Shu3, S. Lindstrom3, N.Simpson3, C. Todd Davis3, A. Mikolon1,3, W.A. Brooks1, T.M. Uyeki3, M. Rahman2,
S.P. Luby1,3, M. Jahangir Hossain1; 1International Centre for Diarrhoeal
Diseases Research, Bangladesh (ICDDR,B), Dhaka, Bangladesh, 2Institute of
Epidemiology, Disease Control and Research (IEDCR), Dhaka, Bangladesh,
3Centers for Disease Control and Prevention (CDC), Atlanta, GA, USA.

Background: Since 2007, highly pathogenic avian influenza A (H5N1)
outbreaks in poultry have been reported each year in Bangladesh. One
previous human case of H5N1 virus infection in Bangladesh was identified
in Dhaka in 2008 through active surveillance for influenza among residents
of Kamalapur, an urban community. In March 2011, the same surveillance
system detected 3 human cases of avian influenza A virus infection, including
2 H5N1 cases and a case of H9N2. A team of epidemiologists, veterinarians
and anthropologists investigated the cases to assess transmission and to
contain further spread. Methods: We collected clinical and exposure history
on the cases. We recorded information on respiratory symptoms among
persons who came within one meter of a case during 3 days before a case’s
illness onset to 7 days after last detection of H5N1 or H9N2 virus in followup
nasopharyngeal wash (NPW). We collected serum samples from cases
and from contacts who reported respiratory symptoms. NPW samples were
tested at IEDCR and ICDDR,B for influenza viruses by RT-PCR. Serology, virus
isolation and further characterization were done at CDC, Atlanta.

Results:
All 3 cases were <5 years old, previously healthy, and presented with fever,
cough and/or runny nose. One H5N1 case had received oseltamivir treatment.
All recovered without hospitalization and without complications. All cases
had a history of poultry contact; the median time from contact to illness
onset was 7 days (range: 7-10 days). Five of the 57 interviewed contacts
of cases had a history of respiratory symptoms. None of the contacts had
serological evidence of H5N1 virus infection. H5N1 viruses were isolated
from two cases and identified as clade 2.2 viruses, closely related to highly
pathogenic H5N1 viruses circulating among poultry in Bangladesh. A virus
isolated from the third case was identified as a low pathogenic H9N2
virus, G1 lineage. All isolates were sensitive to 3 neuraminidase inhibitors.

Conclusion: Detection of mild pediatric cases of avian influenza A virus
infection through active community surveillance suggests that additional
cases may be undetected in other areas of Bangladesh and highlights the
importance of surveillance in areas where avian influenza in poultry is
endemic, in order to assess the risk of human infection with novel influenza
A viruses.