SUMMARY: Studies carried out in the states of Maharashtra, Gujarat, Uttar Pradesh and Union Territory of Delhi after the bubonic plague outbreak during 1994 revealed the presence of seven species of rodents, viz. Rattus rattus, R. norvegicus, Mus. musculus, Tat era indica, Suncus murinus, Bandicoota bengalensis and B. indica. The flea species encountered were Xenopsylla cheopis and X. astia. The X. cheopis and X. astia index recorded in different areas of Beed district of Maharashtra; Surat, Vadodra and Baruch districts in Gujarat and Varanasi district in Uttar Pradesh and their implications have been discussed. Insecticide suspectibility tests carried out against DDT, dieldrin, malathion and deltamethrin with X. cheopis collected from Maharashtra, Delhi and Varanasi revealed that this vector species is resistant to DDT and dieldrin but susceptible to malathion and deltamethrin. The prevalence and distribution of rodents species, high cheopis index and prevalence of Tatera indica just at the door steps of houses in village Mamla of Beed district provides highly congenital conditions for the intermingling of wild and domestic rodents and transfer of flea population from wild to domestic rodents and vice-versa. These conditions were found to be highly supportive for bubonic plague transmission in the district. The presence of Yersinia pestis antibodies in Rattus rattus collected from Beed, Surat and Varanasi areas are also indicative of bubonic plague in Beed and Varanasi and pneumonic plague in Surat during 1994.97

SUMMARY: Lymphatic filariasis is the second leading cause of long-term disability in the world. In India, filariasis is endemic in 250 districts in 20 states and union territories with about 553 million people at risk of infection. Temephos is being used as a larvicide to control the population of Culex quinquefasciatus mosquito, the vector of bancroftian filariasis. The susceptibility status of Cx. quinquefasciatus to temephos in various urban zones of Delhi and the national capital region (NCR) was evaluated using the WHO standard susceptibility test kit. Results of the test revealed that the larval mortality in urban zones ranged from 2.8 to 56.5z, while that in rural zones ranged from 45.0 to 71.0z. Among the urban zones, the lowest larval mortality was recorded from Karol Bagh zone (2.8z) and highest mortality was recorded from Shahdara South zone (56.5z). In the NCR, the larvae were collected from the areas surrounding Delhi, and the larval mortality ranged from 75.0 to 87.5z. The present study indicates the possible development of resistance against temephos in the larvae of Cx. quinquefasciatus mosquitoes in some urban areas.

A study on the vector prevalence of Scrub typhus was undertaken in the Scrub typhus affected areas in Lunglei district, Mizoram. Rodents were trapped using live traps and examined for ectoparasites and serological test for scrub typhus antibodies was also done. Results on the vectors of the Scrub typhus revealed the presence of the vector mite Leptotrombidium deliense on the rats in 3 localities of Haulawng village. Chigger index was found to be 12.33, which is above the critical index of 0.69 per rodent. Chigger infestation rate was 18.5. The chigger infestation was found mainly on Rattus rattus. Detection of Orientia (Scrub typhus) 1:20 and 1:80 has been calculated by Weil Felix OXK antigen. Observation of the vector of Scrub typhus warrants regular surveillance in these areas to prevent any impending outbreak.

Vector borne diseases are a major public health problem in India. Dengue is endemic in almost all states and union territories. Aedes mosquitoes are known to transmit Dengue, Chikungunya, Zika virus and Yellow fever diseases to man in both rural and urban areas. Dengue has been restricted to urban area, but it has now spread to rural and tribal areas. An entomological survey was undertaken at selected villages of three Blocks of Pakur district i.e. Pakur, Maheshpur and Amarpada of Jharkhand to know the potential for the transmission of Dengue/Chikungunya, Zika virus and Yellow fever and thereby undertaking surveys of breeding places of the vector species in these area by assessing the vector indices i.e. House Index (HI), Breteau Index (BI) and Container Index (CI) along with virus antigen detection. The entomological indices of G aneshpura, Datiapokhar and Longbahra villages of Maheshpur block recorded very high i.e. HI-28.5, 15.0 & 10.0; BI-34.2, 15.0 & 10.0 and CI-11.8, 8.8 & 4.8 respectively. The entomological indices of Pakur block, villages Jamsherpur, Malipada and Gopinathpur showed HI-7.3, 3.3 & 2.3; BI-7.3, 3.3 & 2.3 and CI-3.5, 1.5 & 1.3 respectively. The entomological indices of Amarpada block, villages-Jagjitpur, Ambajora and Pakudh showed HI-6.6, 0.0 & 0.0; BI-6.6, 0.0 & 0.0; and CI-2.5, 0.0 & 0.00 respectively. However, surveys revealed highest vector indices at Maheshpur block, followed by Pakur block and Amarpada block. Local health authorities of Maheshpur, Pakur and Amarpada blocks need to take cognizance of these facts with the presence of breeding potential areas and to develop micro action plan for appropriate vector control measures along with vector surveillance on regular basis.

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