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Nipah Outbreak in India
and Bangladesh
India
Between 11 and 28
April 2007, 30 cases of fever with acute respiratory distress and/or
neurological symptoms were reported from Nadia district of West Bengal, Eastern India. The cases presented mainly with fever,
headache and bodyache with a few cases having
episodes of vomiting, disorientation, respiratory distress. Five cases ended
fatally within 3-10 days of onset. Multidisciplinary teams carried out the
outbreak investigation.
The epidemiological
analysis of the five deaths showed that three cases belonged to Betai village (index case, wife and brother-close
contacts), while two were from Krishnanagar town
(also with history of close contact with index cases). Although the index
case did not give any history of travel to Bangladesh, the border is just about
5 km away from the village, where an outbreak of Nipah
virus was confirmed during the same period. Three samples (including urine, CSF, brain and lung tissue from postmortem) from the five
fatal cases were found to be positive for Nipah
Virus by RT-PCR. All these samples tested negative
for flavivirus RNA including dengue.
A similar Nipah virus outbreak was first reported in India in Siliguri
district, West Bengal with high mortality (74%) in January and February 2001
also following a similar outbreak in Bangladesh.
Dr Sampath Krishanan, WHO NPO, India
Bangladesh
Nipah
outbreak was first documented in Bangladesh in 2001. Then in January 2003, a similar outbreak
was reported in Naogaon districtat
a distance of 150 km from village reporting the first outbreak. More recently two separate outbreaks in Thakurgaon and Kushtia were
identified through a surveillance system set up in collaboration with the Institute of Epidemiology, Disease Control and
Research (IEDCR) and ICDDRB. In both situations, Nipah
cases were defined as persons residing in the affected areas that have fever
with new onset of seizures or altered neurological status. The details are as follows. The index case in Thakurgaon
outbreak occurred in January and thereafter over a period of 4 weeks, 7 cases
were reported out of which 3 died (case fatality rate=43%) of them were young
adult males. No occupational
association can be established from available information. Death occurred within 5-7 days of onset of
disease. (Fig. 2)
The second outbreak
in Khustia began in third week of March. 8 cases
were reported out of which 5 were fatal (case fatality rate=62%). (Fig. 3)
The mean age of cases was 38 years and most of the affected were
females. Most of the cases were rice firm
workers. All the cases were manifested
with fever with a majority of them experiencing fatigue and weakness. Neurological manifestations were found in 63%
of cases. On an average death occurred
within 4 days of onset of disease.
The data suggest
strongly that infections were probably transmitted by close personal contact
with the initial case.
Laboratory
Investigations: Serum samples and throat swab have been taken from five cases
in Thakurgaon CSF was
also collected from one of the cases from Thakurgaon.
In Kushtia serum samples, throat swab and nasal
swab could be collected from only three of the cases. Samples were tested for
IgM against Nipah Virus
using Elisa method on priority basis in IEDCR
laboratory. All the serum and CSF samples (from Thakurgaon
and Kushtia) were then shifted to CDC, Atlanta for
reconfirmation.
Md Kamruzzaman Biswas, WHO, Bangladesh
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