Pathology of a H5N1, highly pathogenic avian influenza virus, in two Indian native chicken breeds and a synthetic broiler line.

In this study, susceptibility to H5N1 virus infection was studied in two Indian native chicken breeds viz. Kadaknath and Aseel (Peela) and an Indian synthetic broiler strain (Synthetic dam line (SDL-IC). Fifty birds from each genetic group were infected intra-nasally with 1000 EID50 of a highly pathogenic avian influenza virus (HPAIV) strain A/chicken/Navapur/India/7972/ 06 (H5N1) and observed for a period of 10 days. Significant differences in severity of clinical signs, gross lesions and time for onset of symptoms were observed. The overall severity of clinical signs and gross lesions was less in SDL-IC broilers as compared to the other two genetic groups. The mortality percentages were 100, 98 and 92% with Mean Death Time (MDT) of 3.12, 5.92 and 6.96 days, respectively for the two native breeds Kadaknath and Aseel (Peela), the and SDL-IC broiler strain. Comparison of histological lesions revealed differences in disease progression among the genetic groups. Vascular lesions such as disseminated intravascular coagulopathy (DIC) were predominant on 3 days post infection (dpi) in Kadaknath, and on 5 and 6 dpi in Aseel (Peela) and SDL-IC broiler. The mean log2 HA titres of the re-isolated virus from various organs of H5N1 AIV infected birds of the three genetic groups ranged from 2.32 (lung, trachea and bursa) to 5.04 (spleen) in Kadaknath; 2.32 (lung) to 6.68 (brain) in Aseel (Peela); and 2.06 (liver) to 7.01 (lungs and kidney) in SDL-IC broiler. These results suggest that the susceptibility to H5N1 highly pathogenic avian influenza virus infection differed among the three breeds; Kadaknath being highest followed by Aseel (Peela) and synthetic SDL-IC broiler.This is possibly the first report on the differences in the susceptibility of the India native breeds to H5N1 virus infection and its severity.

Insecticide treated nets, antimalarials and child survival in India.

Malaria has been a complex public health problem affecting mainly the poor and the rural communities in India. Insecticide treated nets (ITN) and antimalarials are the two proven interventions for prevention and control of malaria. ITN has been amply demonstrated to be an effective intervention to protect children from malaria, and in preventing deaths due to falciparum malaria. Antimalarials are a therapeutic intervention for management of malaria, and prevention of complications due to Plasmodium falciparum infection. However, implementation of these interventions is fraught with problems of complex and multidimensional nature at the periphery. These can be addressed by optimizing the use of the 2 interventions, the insecticide treated nets and antimalarials, for area specific application and country specific needs, determined by the eco-epidemiological diversity of malaria in India. This article reviews the significant role of ITN in reducing child mortality, and the judicious use of antimalarials in the management of malaria patient, and the problems associated with the use of these interventions in protecting children against malaria in India.

Investigation of an outbreak of chikungunya in Malegaon Municipal areas of Nasik district, Maharashtra (India) and its control.

BACKGROUND & OBJECTIVES: An outbreak of chikungunya fever occurred in Malegaon town of Nasik district of Maharashtra state, India during February and March 2006. A total of 4530 fever cases were reported during this period including 1781 cases which were admitted in different hospitals of the town. An entomological and epidemiological investigation was carried out in the affected villages during the outbreak to study the possible causes of the outbreak and to isolate the virus responsible. METHODS: Entomological evaluation was done as per WHO guidelines. Sera samples were collected by venipuncture from clinically suspected chikungunya patients in hospitals and also during house-to-house survey in affected villages. IgM antibodies to dengue virus were detected using IgM capture ELISA (PANBIO) and by "Haemagglutination inhibition test" for detection of antibodies against Chikungunya virus. Acute sera samples were inoculated in cell lines for virus isolation. The isolates were confirmed by RT-PCR. RESULTS: On investigation, it was found that water storage containers like cement tanks, plastic containers or earthen pots placed in front of the individual houses were the potential breeding sites for Aedes aegypti. Entomological survey carried out in the most affected areas revealed high Aedes indices. House, container and breteau indices were found to be 27.2, 16.19 and 35.1, respectively. Out of the 13 acute sera samples collected, virus was isolated in 10 samples. The isolates were confirmed by RT-PCR and sequencing using primers from nsP1 gene of Chikungunya virus (CHIKV, Accession No. EF077609, EF077610). Of the 17 convalescent sera tested, significant level of HI antibodies to CHIKV was detected in five samples. One sample was positive for IgM antibodies against dengue virus. Based on clinico-epidemiological features and laboratory findings, the illness was confirmed to be of chikungunya viral disease. CONCLUSION: Control measures targeting the vector population and personal protective measures against the mosquito bites were instituted. Extensive IEC campaign with the involvement of community and religious leaders helped in containment of the disease.

Entomological indices of Aedes aegypti at some international airports and seaports of southern India--a report.

Entomological surveys were undertaken at some of the international airports/seaports (Bangalore, Calicut, Chennai, Cochin, Thiruvanathapuram and Vishakapatnam) to find out the breeding prevalence of dengue vector mosquito in diverse breeding containers from 1998 to 2004. Three vector indices (House index, Container index and Breateu index) were used to assess the breeding potential at each airport/seaport. International Health Regulations urged national governments to keep all the international airports/seaports and peripheral areas up to 400 meters free from Aedes aegypti mosquitoes. However, surveys revealed high vector indices at all the airports and seaports. Health authorities of airports/seaports need to take cognizance of these facts and develop action plan for appropriate control measures with emphasis on vector surveillance.

First time detection of Japanese encephalitis virus antigen in dry and unpreserved mosquito Culex tritaeniorhynchus Giles, 1901, from Karnal district of Haryana state of India.

Japanese encephalitis virus (JEV) antigen has been detected by antigen capture enzyme linked immunosorbentassay (ELISA) in dry specimens of the mosquito Culex tritaeniorhynchus Giles, 1901, collected from Karnal district of Haryana state in northern India. These mosquitoes were stored in dry condition for 20 months, at room temperature, before processing. The procedure of detecting JEV infection in long time stored, dry vector mosquitoes, has important application in the surveillance of Japanese encephalitis.

Outbreak investigation of scrub Typhus in Himachal Pradesh (India).

Scrub Typhus outbreak investigation was undertaken during September 2003 in the three worst affected districts Shimla, Solan and Sirmaur in Himachal Pradesh (India). A total of 113 cases and 19 deaths (17.27 percent case fatality rate) were reported from the eight districts, which were reporting cases. Cases were prevalent in all age groups and in both the sexes among the persons frequenting forest for occupational work. 35.7 percent of the patients serum samples showed a titer of > 1: 80 against OX 19 and OXK antigen is suggestive of Scrub Typhus. Entomologically Rattus rattus (39.5 per cent) was the most prevalent species followed by Suncus murinus (22.91 percent), Bandicoota bengalensis (29.16 percent) and Bandicoota indica and Mus musculus (4.16 percent each). Vector species Leptotrombidium deliense and Gahrliepia (schoengastilla) sp. were recorded. The chigger index 23.0 was found to be highest in Vill. Baldian and 5.0 in Vill. Bhatakuffer (Shimla) and 1.0 in Vill. Rebon (Solan), which is above the critical limit of 0.69 per rodents. Other mite species, ixodid ticks, fleas and lice have been recorded.

Study on susceptibility status in aquatic and adult stages of Aedes aegypti and Ae. albopictus against insecticides at international airports of south India.

A study on susceptibility status in aquatic and adult stages of Aedes aegypti and Ae. albopictus was undertaken at International Airports of Thiruvananthapuram and Cochin located in southern India. WHO standard test kits were used to conduct insecticide susceptibility tests against various organophosphates, organochlorines, carbamates and synthetic pyrethroids. The results indicate that adult Aedes aegypti and Ae. albopictus were resistant to DDT and dieldrin, but susceptible to propoxur, fenitrothion, malathion, deltamethrin, permethrin and lambdacyhalothrin. The susceptibility test conducted on immature stages of Ae. aegypti and Ae. albopictus revealed that they are susceptible to the larvicides commonly used under the National Vector Borne Diseases Control Programme viz. Temephos (0.02 ppm), Fenthion (0.05 ppm) Malathion (1.0 ppm) and Fenitrothion (0.06 ppm).

Surveillance of dengue vector at thiruvananthapuram (Kerala) International Airport.

A survey of Aedes (Stegomyia) mosquitoes was undertaken in and around the International airport at Thiruvananthapuram during premonsoon season. An attempt has been made in this paper to elaborate on the presence of risk potential for Dengue /yellow fever at the airport with the detection of Aedes breeding. The entomological indices have also been discussed with regard to presence of potential wet containers and rate of infestation by Aedes mosquitoes. The airport area was searched for Aedes (Stegomyia) breeding where 20% of the premises were found positive for Aedes aegypti breeding and one premise (6.6%) was found positive with Aedes albopictus breeding. In the 400 meters (perimeter) of airport, four municipal wards namely Chakka, Sankumugam, Valiyathura and Vettucadu were surveyed. The house index ranged from 5.8% to 11.7% for Aedes aegypti while, it was between 9.8% to 19.2% with regard to Aedes albopictus. The container index ranged between 4.4% to 9.9% for Aedes aegypti and 7.1% to 15.3% for Aedes albopictus. Breteau index was found to be between 23.5% to 51.9% for both the species. The susceptibility test conducted against different insecticides showed that the immature stages of Ae. aegypti and Ae. albopictus were found to be susceptible to the commonly used larvicides in public health viz. Temephos (0.02 ppm), Fenthion (0.05 ppm), Malathion (1.0 ppm) and Fenitrothion (0.06 ppm).

Outdoor resting preference of Culex tritaeniorhynchus, the vector of Japanese encephalitis in Warangal and Karim Nagar districts, Andhra Pradesh.

BACKGROUND & OBJECTIVES: Entomological investigations were carried out in Warangal and Karim Nagar districts of Andhra Pradesh during viral encephalitis outbreak in July 2003. METHODS: Adult mosquito collections in outdoor were done using sweep cage method and in indoor with the help of aspirator tube and flash light. Larval collections were done by dipping method. JE virus positivity was tested by IgM capture ELISA test. RESULTS: Outdoor collections revealed presence of Culex tritaeniorhynchus, Cx. bitaeniorhynchus and Cx. gelidus and in indoor collections--Cx. quinquefasciatus, Cx. tritaeniorhynchus, An. vagus and An. subpictus. In the outdoor collections Cx. tritaeniorhynchus was predominant (96.3% of total collection). Three samples out of 55 serum samples from human cases and five from contacts showed the presence of antibodies against JE virus. INTERPRETATION & CONCLUSION: Cx. tritaeniorhynchus, a known vector of JE is predominant in outdoors and playing a main role in JE transmission in this area. Vector control aimed at the outdoor resting population might limit virus circulation in the mosquito vertebrate host cycle and prevent human infection.

Eco-epidemiological characteristics of an unstable peri-urban focus of falciparum malaria.

Two fever surveys were carried out in Shahbad dairy, Delhi in the post-monsoon months of October and November, 1996. Shahbad dairy is a peri-urban locality in the northern periphery of Delhi. The prevalence of fever was found to be 11.6% in October and 2% in November. In the two surveys a total of 21 (28%) fever cases were found infected with malaria (17 with P. falciparum and 4 with P. vivax). The prevalence of malaria in the surveyed population was lower (25%) in October than in November (36.8%). More adults and males suffered from malaria than other age groups and the females. In November the mean asexual parasitaemia, for P. falciparum infection, sharply declined among 5-14-years old children by 68%, but among adults it increased by 32%. Collection of adult mosquitoes, from human houses, revealed the presence of 5 species of anopheline mosquitoes comprising Anopheles culicifacies, An. stephensi, An. annularis, An. subpictus, and An. nigerrimus, and a culicine mosquito Culex vishnui complex. Extensive breeding of these mosquitoes was detected in the vicinity of Shahbad dairy. Characteristic ecological support system (ESS) for malaria transmission was identified at the peri-urban focus of Shahbad dairy.

Absence of wild poliovirus circulation among healthy children in a rural area with high oral poliovirus vaccination coverage.

Poliovirus circulation in a rural community was studied by a stool sample survey. No acute paralytic poliomyelitis case had been reported from the study area during the previous 5 months. Immunization coverage in age groups 7 to 12 months and 12 to 60 months was 95.8 and 94 per cent, respectively. Of the 257 children from whom stool samples were collected (about 6% of the child population), 161 (62.6%) were positive for virus isolation. Poliovirus was isolated from 60 (23.3%) children. All three poliovirus types were detected (41 type 1, 16 type 2 and 3 type 3). Intratypic differentiation tests classified these isolates as vaccine-like. Among the children excreting poliovirus, the proportion of those who did not receive polio vaccine within 30 days prior to the sample collection was 46.3, and 68.7 per cent for poliovirus type 1 and 2, respectively. It was concluded that these poliovirus excreting children were infected by the vaccine strains circulating in the environment. The survey showed that wild poliovirus was not detectable within five months after the last case of acute poliomyelitis. Displacement of the wild virus from the environment and circulation of vaccine virus was achieved by high vaccination coverage in this area.

An unusual morphological type of Trypanosoma (Herpetosoma) lewisi (Kent, 1880) detected in the blood of Rattus norvegicus in India.

An unusual morphological type of Trypanosoma (Herpetosoma) lewisi (Kent, 1880) which was detected in Rattus norvegicus in India is reported in the present study. This type is different from known types of T. lewisi in that the kinetoplast is at a greater distance from the posterior end (P-K) than the usual type. The total length, including the free flagellum, is 35.3-39.3 microns and P-K is 11.9-15.0 as against total length of 21 to 36.5 microns in the normal form.

Critical appraisal of entomological data of Madhya Pradesh for 1991 and its relevance to the National Malaria Eradication Programme.

Entomological data generated in five entomological zones, of Madhya Pradesh State during 1991 including, Bhopal, Bilaspur, Gwalior, Indore and Raipur were analyzed. The entomological parameters that were studied included per man hour (pmh) density, abdominal physiology and parity status. The inferences were related to i) resting behaviour (exophily/endophily) ii) duration of indoor resting period of mosquitoes iii) man-vector contact iv) efficacy of residual insecticide and v) vulnerability of the area to focal malaria outbreaks. The data chiefly pertains to the putative malaria vector Anopheles culicifacies in all the five zones under study. The studies have brought out that A. culicifacies, traditionally endophilic and endophagic, has demonstrated radical departure in its resting and feeding behaviour. In Gwalior zone the species shows high preference for exophily. In Bhopal and Indore zones there is differential resting behaviour with respect to season. The species shows, for most part of the year exophily but is also endophilic during post monsoon period. In Bilaspur zone the species shows marked exophily and endophagy. Irrigation practices seem to have affected the mosquito population density patterns in these regions as brought out in Indore and Bilaspur zone, where high density pattern is observed between November and February. These findings have obvious implications in selecting the appropriate intervention methods and the period of spray in areas where residual spray is the method of choice for interruption of transmission.

Biometrical variations in haematophagous arthropods. II. DV/D ratio of male terminalia of wild Culex quinquefasciatus SAY (Diptera: Culicidae) in India.

The DV/D ratio of male terminalia is considered as most reliable morphometric feature to distinguish Culex pipiens from Cx. quinquefasciatus. In India although only Cx. quinquefasciatus is known both in the filariasis (Bancroftian) endemic and non-endemic areas, there has been no study on the amounts of morphometric variation among wild strains of this species. This paper reports variation in the DV/D ratio of Cx. quinquefasciatus collected from 7 localities of Delhi (D), Lucknow (L), Patna (P), Varanasi (V), Rajahmundry (R), Jabua (J) and Alleppey (A) between June and October 1986. The mean value of DV/D ratio in all the strains varied from 0.78 to 0.99 with overall mean of 0.89. The range of the ratios was 0.30 to 1.88. There were 1.28 per cent specimens (9 out of 700) with ratio below 0.50 and the rest 98.72 per cent with ratio 0.50 and above. The DV/D ratio of 0.50 should therefore be accepted as lower limit for Cx. quinquefasciatus instead of the earlier established value of 0.40. The coefficient of variation (CV) among the 7 strains indicates the following progression of variability in the DV/D ratio from most stable to most variable strain: L greater than V greater than R greater than A greater than J greater than P greater than D. The range of mean CV values in different strains was very close with most stable L strain 19.19 and most variable D strain 25.92. The amounts of variation, as estimated by coefficient of variation, were found to be significantly different between the following strains: Delhi and Lucknow (P less than 0.01 at 198 df), Lucknow and Patna (P less than 0.05 at 198 df), and Delhi and Varanasi (P less than 0.05 at 198 df).(ABSTRACT TRUNCATED AT 250 WORDS)