Chikungunya being confused with dengue fever

Experts started suggesting that the recent dengue fever outbreak being reported from scattered areas of the country also include cases of Chikungunya, a less severe and rarely fatal form of viral hemorrhagic fever.

“After thorough assessment of the situation, I along with my team reached a conclusion that it is predominantly Chikungunya being confused with dengue fever,” said Head of Pathology Department at Rawalpindi Medical College Dr Abbas Hayat while talking to ‘The News’ Friday.

He said that on serological examination of 40 highly suspected dengue victims, only three were found infected with dengue fever virus so it is mainly Chikungunya that has also been feared as Dengue Hemorrhagic Fever in a few cases. “It resembles dengue in its transmission through Aedes Aegypti mosquito although it has also been reported to be spread by another specie Aedes Albopictus.”

He said that Chikungunya also shares with dengue the symptoms including fever, rashes and joint pain yet differs from it in sparing muscles and being less severe and rarely fatal. “Dengue fever is caused by a Flavi virus while Chikungunya is caused by alphavirus,” he said and added that in neighbourhood, Chikungunya has appeared in an epidemic form in the Indian states including Karnataka, Tamil Nadu, Kerala, Maharashtra and Andhra Pradesh. Reverse Transcriptase-PCR testing which is not currently available in local settings is used for confirmation of Chikungunya.

“On the basis of current reports and Regional studies, it is deducted that most likely it is Chikungunya which is being confused with dengue fever, so the higher authorities are requested to make arrangement for detailed studies and devise policy according to the problem,” said Dr Hayat.

He added that in recent months, many cases of suspected dengue fever in various Pakistani cities failed to be confirmed on serologic testing. “There should be a high index of suspicion for these cases to be of Chikungunya disease since the clinical presentation of the two is very similar. And serologic testing for Chikungunya virus should be performed on all cases that have a negative serology for dengue virus,” he said and added that in October 2006, more than a dozen cases of Chikungunya were reported in Pakistan.

Chikungunya virus (CHIKV) is an arbovirus, of the genus Alphavirus, which causes an illness with symptoms similar to dengue fever. CHIKV is generally spread through bites from Aedes Aegypti mosquitoes (also the vector for dengue fever) but recent research by the Pasteur Institute in Paris has suggested that Chikungunya virus strains in the 2005-2006 Reunion Island outbreak resulted in a mutation that facilitated transmission by Aedes Albopictus (Tiger mosquito), added Dr Hayat.

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Sting operation

Mosquitoes seem to have hit the city with a vengeance. According to figures released by the government, vector-borne diseases such as dengue, malaria and Japanese encephalitis have taken 26 lives in Calcutta. However, media reports claim that the figure is higher, 33.

As the incidence of malaria and dengue rises, so does the sale of mosquito repellents. Whether it is coils, liquid vapourisers, lotions, creams or aerosols — repellents of all kinds are selling like hot cakes. “The sale of major brands of mosquito repellents has increased by about 15-20 per cent over the past month,” says Samar Singh Sheikhawat, vice-president, marketing, Spencer’s Retail.

That may be good news for retailers, but consumers need to be aware that mosquito repellents can have certain potential side effects. Medical experts warn that excessive use of these products for long periods is bad for health. “Nervous weakness is an important side effect of chemicals used in mosquito repellents,” says Dr Pulak Lahiri, Nilratan Sarkar Professor of Zoology at Calcutta University.

“According to the National Occupational Health and Safety Commission, the US, long-term use of Alithrin and Prallethrin, the two major chemicals in these products, are hazardous to human health. They primarily affect our respiratory and immune systems, and in extreme cases, even our nervous system,” he adds.

Most health experts echo Dr Lahiri’s concern. “Smoke-based mosquito repellents such as coils can trigger wheezing attacks, specially in those who are prone to allergies and asthma,” says Dr Narayan Bhattacharya, a city-based general practitioner. “Coils and aerosol sprays are the worst offenders and their toxic fumes should be strictly avoided.”

Naturally, companies that sell mosquito repellents insist that their products are risk free. “The chemicals are present in such small quantities that they have an effect only on mosquitoes. Coils and aerosols cut off the oxygen supply for mosquitoes in the upper layers of the air, causing them to become inactive,” says Subrata Chakraborty of Reckitt Benckiser, which markets mosquito repellents under the brand name Mortein. “They do not harm humans if used in a well-ventilated room,” he asserts. He also mentions that Mortein carries a toll-free number that a consumer can call to lodge a complaint if he or she suffers any health problem on use.

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Northern sting

Northern Australia is much closer to Australia’s neighbours than we are down south. Papua New Guinea is only 3km from Queensland’s outer islands. Sydney is a three-hour flight from our only southern neighbour. The expansive Tasman Sea is less a “ditch” than the narrow Torres Strait or Timor Gap.

Not only is the north much closer to many more of Australia’s neighbours, these countries face many more grave problems that can spill over into Australia. We have seen this with tuberculosis in far north Queensland.

Climate change could well aggravate these geographical realities, place greater demands on local public health services and require deeper co-ordination between the Commonwealth and the northern states.

While climate change may sink Tuvalu and Kiribati, it is making larger parts of the Pacific Islands, Indonesia and the Philippines more hospitable to mosquitoes bearing malaria and dengue fever.

Within Australia, the effects of climate change are bad for mosquitoes in southern Australia, but good for them in the north. Conditions may improve for malaria-carrying mosquitoes as far south as Gladstone, while dengue-carrying mosquitoes could migrate downwards to Rockhampton.

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Mozziesafe Launched by UNICEF Country Representative

mozziesafe was officially launched by the Hon. Youssouf Mohammad Oomar, Country Representative of Malaysia of the United Nations Children’s Fund (UNICEF). The launch took place as a highlight of the 39th Installation of the President & Board of Directors of the Rotary Club of Gombak, at the Equatorial Hotel in Kuala Lumpur, Malaysia, on Sunday, 3 August 2008. Read more