While winter is usually the season for colds, coughs and other viral fevers, the city is already in the grip of viral fevers that are vector- borne. Chikungunya and Dengue are rampant in the city with hospitals and nursing homes getting a steady flow of patients. Some of the bigger hospitals are also receiving cases from neighbouring districts. Though Chikungunya and Dengue are both Haemorrhagic fevers (patients exhibiting rashes), the diseases are manifesting themselves in very atypical forms. The city health authorities are, therefore, quick to say that there are no Chikungunya cases in the city.

General physician P.S. Rao says doctors are facing difficulty in diagnosing the diseases because of the absence of rashes that are typical of Haemorrhagic fevers.

Though the patients are not being so ‘incapacitated’ by it, the fever is without any doubt Chikungunya, says paediatrician Yelamanchili Sandhya. When affected by more virulent strains of the disease, patients suffer for up to six months but the strains doing rounds in the city are milder with patients recovering from joint pains within a week or 10 days, she says.

Vijetha Hospital chief P.M.C. Naidu says that several Dengue cases are being treated in their hospital. Thanks to good blood banks in the city, blood platelets that are required for treating the diseases are easily available. Earlier whole- blood had to be given to patients despite side-effects, he says.

Both the diseases are spread by Aedes Aegypti, a variety of mosquito that bites during the day. Most other mosquito species are crepuscular (dawn or dusk) feeders. Entomologists say the Aedes mosquitoes’ search for a host takes place in two phases.

To begin with, the mosquito exhibits a non-specific search, but once the host is perceived it uses the target approach. The mosquitoes are known to bite the host repeatedly.

Easy targets

Even doctors have fallen prey to these vector borne diseases. Diabetes patients with lesser body resistance are easy targets for these diseases. “Several diabetic patients are suffering from Chikungunya and several doctors with diabetes are suffering from Dengue,” says a diabetician. Virus isolation provides the most definitive diagnosis of Chikungunya, but it takes one to two weeks for completion and can be carried out only in Biosafety level-3 laboratories. CPI (M) corporator Ch. Babu Rao says Vijayawada Municipal Corporation (VMC) has completely abandoned fogging and even reduced the anti-larval activity. The Communist Party of India (Marxist) has been conducting a door-to-door survey in areas with mosquito problems to establish the severity of the problem, he says.

There should be a drive to make schools and work places mosquito-free because of the feeding behaviour of Aedes mosquitoes. Even private pest control agencies can be pressed into service to achieve this target, says a VMC official.

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