Experts focus on reducing viraemia to counter Zika threat in Pune
According to experts, a strict cycle to eliminate horizontal transmission from adult mosquitoes and vertical transmission in the larvae will help reduce the transmission of Zika virus
To combat the Zika virus disease threat in Maharashtra, especially Pune city, experts from the National Centre for Vector Borne Diseases Control (NCVBDC), ministry of health and family welfare (MoHFW), have decided to focus on reducing viraemia and transmission of the virus in the vector, officials said.
Dr Sarita Sakpal, senior regional director (Maharashtra, Goa, and Daman & Diu), NCVBDC, said, “The infected adult mosquitoes will be eliminated, including the larvae which might be carrying the virus. The patients who are infected with Zika virus will be protected from mosquito bites to prevent mosquitoes from being infected with the Zika virus.”
Dr Sakpal further said that the current spread of Zika virus will be contained if we follow this, and it has to be followed strictly for 14 days. The patients who have tested positive for Zika virus will be asked to use mosquito repellent creams, liquids, coils, mats etc. Furthermore, they will be asked to wear full sleeve shirts and full pants with socks and use bed nets to prevent mosquito bites, she informed.
“Containment activities will kill the infected mosquitoes but new mosquitoes can get infected with the virus and spread it to other people. The Zika-infected patients cannot be isolated so they will be asked to live in a mosquito-free environment. Eventually, everyone should follow the personal prophylactic measures to prevent vector-borne diseases,” Dr Sakpal said.
According to experts, a strict cycle to eliminate horizontal transmission from adult mosquitoes and vertical transmission in the larvae will help reduce the transmission of Zika virus. There is a system developed in rural areas with a hierarchy that is not seriously followed in the municipal corporation areas of Pune, Mumbai, Nashik and Kolhapur among others. Due to this, there is a high prevalence of vector-borne diseases like dengue and chikungunya in these areas, they said.
Another senior official from NCVBDC stated, “If we can take control of adult mosquitoes and larvae laid by infected mosquitoes, the viraemia in the vector mosquitoes will be reduced. If we protect Zika patients from mosquito bites, preventing the virus from being introduced to new people, we can stop active transmission. Zika virus transmission and cases can be significantly reduced.”
Zika virus is primarily transmitted through the bite of an infected Aedes mosquito and Aedes Albopictus, known to transmit infections like dengue and chikungunya. A majority of those infected with Zika either remain asymptomatic (up to 80%) or show mild symptoms of fever, rash, conjunctivitis, body ache, and joint pain. Maharashtra this year has reported 21 cases of Zika virus out of which, 19 have been reported in Pune district within a month.
NCVBDC in India works towards the effective implementation of guidelines and policies issued by the central government for prevention and elimination of vector-borne diseases in the country. The experts are also trying to develop a robust system or micro action plan to control the vector for Zika, dengue and chikungunya.
NCVBDC experts to train PMC staff
Pune city reported its first case of Zika virus infection on June 20 after which surveillance and containment activities were started by the Pune Municipal Corporation (PMC) insect control department and health department. However, experts at NCVBDC said that only the right efforts in the right direction will give results.
Dr Sarita Sakpal said that for every species of mosquito, the habits of mosquitoes like biting, feeding and resting differ. The current rain cycle makes for adequate locations for mosquito breeding. “In Zika-affected areas, the vertical transmission of the virus can occur when an infected female mosquito lays eggs. The new mosquitoes will also have virus infection. Larvicidal activity is important in such an area which has to be carried out following the seven-day cycle,” she said.
The NCVBDC on Thursday conducted the first training session for PMC officials and staff from the health department and insect control department to manage and prevent the further transmission of Zika virus infection in the city. The entomologists explained the integrated vector control approach to eliminate mosquito breeding and prevention, said Dr Rajesh Dighe, assistant health officer of the PMC.
PMC health officials have been asked not only to focus on Aedes Aegypti but also other species like Aedes Albopictus and Aedes Japonicus during the containment activities. “The biological control and use of larvivorous fishes in ornamental tanks, fountains, etc. and aerosol space spray. The right quantity of insecticides during biological and chemical control was discussed, during the training,” said Dr Dighe.
Dr Sakpal said that the PMC has mostly contractual staff working in the insect control department, and most of them are not updated with the containment activities. “The training session was conducted as part of the Zika virus prevention and elimination activity. If they are not going in the right direction, the measures are not going to be helpful,” she said.
The senior regional director of NCVBDC further informed the vectors for Zika, dengue and chikungunya are the same and that the activity will help prevent other vector-borne diseases too. “If we work on containment of one disease, the other diseases will eventually come under control. Vector control is not just the work of the health department but requires support from water, building and other departments. Even the public should participate and support the administration in eliminating and preventing mosquito breeding,” she said.
Zika cases in Maha
2021: 27 cases
2022: 3 cases
2023: 15 cases
2024: 21 cases (18 in Pune city; and one each in Saswad (Pune rural), Kolhapur and Sangamner)