Chikungunya could be fatal, indicates study

The study conducted by the Indian Institute of Management, Ahmedabad (IIM-A) gathered data from the health department, municipal hospitals and health centres and the registrar,  births and deaths, of Ahmedabad.

The data pointed to the fact that compared to the expected deaths per month in previous years, excess deaths were noticed during the period when chikungunya outbreak was at the peak. This despite the fact that the official report indicated 1.39 million cases of chikungunya in the country in the same year, with no deaths.

The study holds relevance to Karnataka, since 7,62,026 people were suspected to have had chikungunya in 2006. “The districts in the north and south of the State were struck by the chikungunya epidemic in 2006-07. In 2008, however, we saw newer districts that had not been affected earlier falling prey to the epidemic like Udupi and Dakshina Kannada. But chikungunya has not caused deaths, till now,” said Dr T S Cheluvaraju, joint director (communicable diseases), health department. However, he admitted that chikungunya could prove fatal  to those suffering from comorbid conditions.

The Ahmedabad study indicated that the gene sequence of the virus, caused by Aedes mosquito (the same one with dengue virus), was found to be different from the earlier epidemic, which perhaps indicates a mutation and increased virulence. The study was published in “Emerging Infectious Diseases” journal in 2008.

Other fatalities

The first study showing a link between rise in mortality and chikungunya fever was made in the Reunion Island, a French territory, in the Indian Ocean during 2005-06. This was followed by Ahmedabad, Mauritius and the recent Port Blair studies.

Although the Ahmedabad study had a mixed age group of people who had died, the Island figures had people aged above 75 topping the dead list.

Even Mauritius and Port Blair showed excess deaths of 743 and 78 in 2006, respectively. Again, most of the dead were above 60 in Mauritius. The Port Blair study, which was done recently, was accepted by the international journal “Epidemic and Infectious Diseases” and will be published soon.

According to Dr Dileep Mavalankar, who was part of the IIM-A study, older people and those suffering from comorbid conditions were more susceptible to death when contracted by chikungunya. “It’s something new. Those who had severe chikungunya along with comorbid conditions like diabetes, kidney problem, blood pressure, heart diseases, succumbed due to multi-organ failure,” said Dr Mavalankar, who is also dean (academics), Indian Institute of Public Health, Gandhinagar.

What’s needed?

In most hospitals in the Ahmedabad study, the reasons for deaths were reported to be fever, viral fever, multi-organ failure, cardio-respiratory failure, old age, etc. None of them specified any relations to chikungunya. Both the Ahmedabad and Port Blair studies unanimously suggested that detailed studies needed to be conducted on the cause of death in other parts of the country. The maintenance of records of deaths needs improvement.

Past imperfect

* 1963-64: First outbreak of chikungunya in India
* 1973: Last outbreak in Barsi, Maharashtra
* 2005: Fresh outbreak of chikungunya in India after 30 years
* 2006: Chikungunya outbreak in Karnataka

Districts that reported maximum suspected chikungunya fever cases

* 2006 - Bijapur (93,783), Bangalore rural (83,871) and Gulbarga (81,863)
* 2007 - Mysore (429), Hassan (421), Uttara Kannada (248)
* 2008 - Dakshina Kannada (39,042), Udupi (2,014), Kodagu (1,262)
* 2009 - Haveri (12,277), Bangalore City (11,501), Kolar (2,270)
* 2010 (till Nov) - Bangalore City (1,117), Tumkur (1,049), Chikkaballapur (818)

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