Biomedical subjects

K N Panicker

Publications and source records attributed to K N Panicker.

At least 37 records · Page 2Linked to original sources

PubMed1992

The resting and house frequenting behavior of Mansonia annulifera, Ma. uniformis and Ma. indiana, the vectors of Malayan filariasis in Kerala State, India.

Mansonia annulifera, was recorded to be an endophilic species, preferring to rest indoors, while Ma. uniformis was exophilic, having a predilection for outdoor resting habitats, eg bushes and shrubs. Ma. indiana did not show a clear preference to either of these biotopes. In indoor resting collections, the unfed proportion of Ma. uniformis was significantly higher during post-dusk compared to day hours (p < 0.05), indicating that this exophilic species enters houses during dusk hours for feeding. The full fed proportion was higher during day hours compared to dusk/night hours. The semigravid proportion showed a significant reduction during post-dusk hours (p < 0.05). These findings suggest that after having a blood-meal this species rest indoors and leave the houses for outdoor resting sites during the dusk hours on the subsequent night.

Animals↗

PubMed1992

Seasonal abundance, natural survival & resting behaviour of Phlebotomus papatasi (Diptera: Phlebotomidae) in Pondicherry.

A study was carried out on the seasonal abundance, natural survival and resting behaviour of Ph. papatasi in four ecologically different areas of Pondicherry. The average indoor resting density ranged from 2.25 (May 1989) to 16.70/man hour (October 1989). Ph. papatasi was observed to be predominantly endophilic in its resting behaviour. A significant positive correlation was observed between rainfall and relative density. The daily survival of adult population ranged from 0.893 to 0.949 and showed significant positive correlation with relative humidity. Examination of the abdomen of indoor resting females showed that the entire period of gonotrophic cycle was spent indoors.

Animals↗

PubMed1992

Community participation in the control of filariasis.

A programme was launched in 1986 for the control of brugian filariasis in an area of high endemicity in southern India. Sustained community involvement was achieved by integrating economic measures to improve the lot of the people with the creation of widespread awareness about the cause of the disease and about the possibilities of combating it.

Animals↗

PubMed1992

Identification of bloodmeals of phlebotomine sandflies using the agarose gel diffusion method.

The source of blood meal of wild caught Phlebotomid sandflies collected in areas around Pondicherry was identified using an agarose gel diffusion method. A total of 497 blood samples obtained from freshly engorged Phlebotomid sandflies were tested. Of these 66.8% were positive to human antisera, 29.2% to bovine antisera and the remaining 4.0% to avain antisera. The human blood indices of P. papatasi and P. argentipes were 0.91 and 0.04, respectively.

Animals↗

PubMed1992

A cost benefit analysis of fish culture strategy towards the control of mansonioides in Shertallai, Kerala state.

The cost benefit analysis of fish culture as a means for vector control towards the containment of Brugian filariasis in Shertallai, a highly endemic tract for this disease in Kerala was carried out. While the financial gain accrued to the community was to the tune of Rs. 1,82,052 in ponds (under monoculture) with Chinese grass carp from 763 ponds, it was Rs. 1,83,740 from 1000 ponds under polyculture with Catla catla, Cyprinus carpio, Labeo rohita, Labeo fimbriatus, Cirrhina mrigala and Ctenopharyngodon idella (Chinese grass carp). Monoculture with Giant gourami (Osphronemous goramy) fetched an income of Rs. 7,654 to the community from 128 ponds. A marked reduction in weed reinfestation/vector breeding was observed in ponds under fish culture than other without fishes. The study clearly indicates that fish culture is an ideal strategy for Mansonioides control as it can bring perceptible benefits to the community.

Agriculture↗

PubMed1991

Frequency distribution of Brugia malayi microfilariae in human populations.

This study examines the effects of host age and sex on the frequency distribution of Brugia malayi infections in the human host. Microfilarial (mf) counts for a large data base on the epidemiology of brugian filariasis in Shertallai, Kerala, South India are analysed. Frequency distributions of microfilarial counts partitioned by age are successfully described by zero-truncated negative binomial distributions, fitted by maximum likelihood. This analysis provides estimates of the proportion of mf-positive individuals who are identified as negative due to sampling errors, allowing the construction of corrected mf age-prevalence curves, which indicate that the observed prevalence may under-estimate the true figures by between 18 and 47%. There is no evidence from these results for a decrease in the degree of over-dispersion of parasite frequency distributions with host age, such as might be produced by the acquired immunity to infection. This departure from the pattern in bancroftian filariasis (where there is evidence of such decreases in over-dispersion; Das et al. 1990) is discussed in terms of the long history of filariasis control (and consequently low infection prevalence) in Shertallai.

Adolescent↗

PubMed1991

The dynamics of microfilaraemia and its relation with development of disease in periodic Brugia malayi infection in south India.

Rates of acquisition and loss of Brugia malayi microfilaraemia were estimated using the parasitological data of a cohort of population in Shertallai, South India. The rate of acquisition of microfilaraemia was found to be dependent on age but not gender. The decline in the rate of acquisition of microfilaraemia in adults above 35 years could be due to the development of acquired immunity. The mean reproductive lifespan for the periodic Brugia malayi adult female worm was estimated to be 3.4 years and it was independent of host age and gender. The age-specific estimated proportion of population at risk (microfilaria carriers who lost their microfilaria in course of time) of developing lymphoedema approximately mirrored the observed age specific prevalence of lymphoedema in the study population. On an average, 99% of population at risk developed disease in different endemic areas is compared and its epidemiological significance is discussed.

Adolescent↗

PubMed1991

Seasonal abundance & biting behaviour of Mansonia annulifera, M. uniformis & M. indiana & their relative role in the transmission of malayan filariasis in Shertallai (Kerala state).

Three species of Mansonia (Mansonioides) mosquitoes, viz., Mansonia annulifera, M. uniformis and M. indiana were recorded in the Shertallai region of Kerala state. M. annulifera and M. uniformis were recorded throughout the year while M. indiana was seasonal and in small numbers. Their indoor resting density was 3.29, 0.25 and 0.10 per man per h and the man biting density was 24.67, 12.74 and 0.47 per man per night respectively. Vector density fluctuated through seasons and reached a peak during the monsoon/post-monsoon period when there was an increase in the breeding surface area and a relatively higher survival of the adults. The biting tendency of M. annulifera and M. indiana was relatively more indoors (endophagic) whereas it was outdoors (exophagic) for M. uniformis. All these mosquitoes showed a predilection towards cattle, with varying degrees of zoophily. The relative abundance, man biting behaviour and a higher transmission potential indicate that M. annulifera is a more potent vector of Brugia malayi, than M. uniformis in this region.

Animals↗

PubMed1991

Comparison of effects of mass annual and biannual single dose therapy with diethylcarbamazine for the control of Malayan filariasis.

Annual and biannual mass single dose diethylcarbamazine citrate (DEC) at 6 mg/kg body weight was administered to people in a Brugia malayi endemic area in Shertallai part of Kerala, India, in 1987 and 1988. The coverage of population ranged between 41.33% and 66.01% in different rounds. The highest percentage of treated population developing side reactions was 8.4%. Both annual and biannual regimens were effective in reducing the microfilaria prevalence significantly from 4.90% to 1.23% and from 6.27% to 0.62% respectively and the incidence of infection was minimal in the adult population and zero among children. There was significant reduction in mean microfilaria count in both annual (81.08%) and biannual (98.00%) areas. Marked reduction in the proportion of high density carriers and infectivity index of the population after DEC therapy was also observed. Beneficial effect of mass single dose DEC on clinical cases of filariasis was evident from the reduction in the prevalence of acute manifestations, recent edema cases and the proportion of chronic cases with acute episodes. Results obtained from mass treatment areas were compared with those of the control area.

Adolescent↗

PubMed1991

Influence of diethylcarbamazine on the patent period of infection in periodic Brugia malayi.

The patent period of infection which reflects the fecundic life span of the adult female worm was estimated for periodic B. malayi in south India by using immigration death model. Longitudinal data on natural loss of infection or that due to different degrees of DEC pressure in a cohort population of microfilaria carriers after a three years period, were used for the estimations. The patent period of infection was estimated to be 3.45 yr under natural conditions (without DEC therapy), which was reduced to 1.67 yr following one full course of selective therapy (6 mg/kg body wt/day for 12 days). When selective therapy was supplemented with four rounds of biannual single-dose mass DEC therapy (6 mg/kg body wt) the patent period was further reduced to 1.34 yr. The proportion loss of infection was relatively higher in microfilaria carriers who discontinued DEC selective therapy, when compared to natural loss. The percentage reduction in the mean microfilaria count was observed to decrease with increasing DEC pressure. Neither sex nor the age of the host was found to influence the fecundic life span or the survival of female adult worm.

Adolescent↗

PubMed1990

Megaoesophagus in the mouse: histochemical and ultrastructural studies.

Histochemical and ultrastructural studies of the muscle coat of the oesophagus from ICRC/HiCri mice (with megaoesophagus) and DBA/2fNCri mice (normal oesophagus) were carried out. The striking observation from histochemical studies was the presence of smooth muscle in the abdominal segment of the oesophagus from ICRC mouse in contrast to the control strain where smooth muscle was present only in the lowermost portion adjoining the stomach. Ultrastructural studies of the oesophageal wall from 5- and 10-day-old ICRC mice revealed an apparently normal muscle coat. In 3-month-old ICRC mice the upper abdominal segment of the oesophagus showed several abnormalities of smooth muscle fibres and paucity of plexus tissue accompanied by interstitial collagen deposition. The abnormalities were more severe in 1-year-old animals and were seen throughout the abdominal segment. From this study it is suggested that the primary cause of megaoesophagus in ICRC mice is neurogenic and not myogenic.

Adenosine Triphosphatases↗

PubMed1990

Endurance to starvation by the immatures of Toxorhynchites splendens.

Studies on the endurance to starvation by the immatures of T. splendens showed that the III instar larvae survived longer than the I and II instar larvae. The IV instar larvae even in the absence of food pupated and emerged into adults. The irregular supply of food did not affect the perpetuation of the predator in the habitat.

Animals↗

PubMed1990

Choice & integration of different approaches to case detection with special reference to brugian filariasis in south India.

Treatment following rapid case detection in population, particularly the target age classes, which record high prevalence, is necessary for effective control of lymphatic filariasis. Conventional door-to-door surveys resulted in delay in detection of parasite carriers and patients with clinical filariasis, particularly in rural areas. An integration with other approaches like school surveys, health camps, filariasis clinics and microfilaria detection camps (MDC) was found effective in covering a much larger population in brugian filariasis case detection in an endemic area in south India. The MDCs organized through Integrated Child Development Scheme (ICDS MDC) yielded a good coverage of pre-school children. School surveys were ideal in covering children en masse. Community MDCs and health camps arranged with active community participation were useful in covering adolescents and young adults in large numbers. The filariasis clinic was effective in screening older adults above 30 yr. The relative efficiency of these approaches in terms of time and manpower utilization has been discussed.

Adolescent↗

PubMed1990

Weedivorous fishes for the control of vectors of Malayan filariasis.

An attempt was made to assess the efficacy of phytophagous fishes viz., Ctenopharyngodon idella, the Chinese grass carp and Osphronemus goramy, the giant gourami in the control of mansonioides mosquitoes by checking the growth of aquatic weeds which support their breeding. When C. idella and O. goramy were used in monoculture 80.21 and 81.25 per cent of the ponds were kept free from weeds. With polyculture using grass carp in combination with other varieties of carps, only 70.10 per cent of the ponds were kept out from the reinfestation of weeds. Even in the reinfested ponds, there was significant reduction (P less than 0.05) in vector breeding in all the three types of piscicultures, as compared to the control ponds. The utility of weedivorous fishes in the elimination of aquatic weeds and thereby breeding of vectors of Malayan filariasis was thus demonstrated.

Animals↗

PubMed1989

Biting rhythm of the vectors of Malayan filariasis, Mansonia annulifera, M. uniformis & M. indiana in Shertallai (Kerala state), India.

Biting activity of Mansonioides mosquitoes through all night collections for a period of two years in Shertallai region, in south India was studied. M. annulifera bites uniformly throughout the night, with two peaks of activity, one after midnight (24.00-01.00 h) and another before dawn (04.00-05.00 h). M. uniformis was found to be predominantly dusk biting, with its peak of activity between 1800 to 1900 h. M. indiana showed two peaks of biting activity one after dusk (2000-2100 h) and another before dawn (0300-0400 h). All biting, with its peak of activity between 1800 to 1900 h. M. indiana showed two peaks of biting activity one after dusk (2000-2100 h) and another before dawn (0300-0400 h). All these species following a particular pattern of activity cycles discerned the biting rhythm of Mansonioides mosquitoes to be species-specific.

Animals↗

PubMed1989

Giant gourami (Osphronemus goramy: Anabantoidei) as a potential agent for control of weeds, the breeding source for the vectors of Brugia malayi.

The biocontrol efficacy of giant gourami against various aquatic weeds, which form the breeding source of Mansonioides, the vectors of B. malayi, was explored. This fish showed a feeding predilection towards Pistia plant which is the most favoured host of immatures of Mansonioides. A single fish consumed this weed on an average of 206.25 +/- 19.09 g and 316.85 +/- 26.55 g a day under laboratory and field conditions respectively. Techniques developed for the culturing of this fish are also described.

Animals↗

PubMed1989

Attachment behaviour of immatures of Mansonia annulifera (Theobald), 1901.

The detachment and reattachment of the immatures of M. annulifera with their host plants (hydrophytes) is a regular phenomenon. This occurs frequently with the same plant, or with a different one, throughout the larval span. The duration between detachment and reattachment varied from 30 sec to one hour and majority of them get reattached within a minute. This behaviour is instinctive and not found to be influenced by food availability. In the absence of hydrophyte, early immature stages survive relatively longer (192 h), when compared to the late ones.

Animals↗

PubMed1989

Impact of 50 years of vector control on the prevalence of Brugia malayi in Shertallai area of Kerala state.

This article examines the long term effects of vector control on the prevalence of B. malayi infection and disease, by comparing the results of 3 earlier studies (1934, 1955, 1976) in one area of south India with a recent (1986) survey. The data indicate that disease and infection prevalence have declined continuously over the last 50 years. Infection has declined (from 21 to 2%) more markedly than disease (from 24 to 10%). Age-specific data indicate that this difference is due to the irreversibility of the clinical signs and the long term survival of diseased cohorts. The results indicate that the prevalence of clinical brugian filariasis can be reduced using vector control and that such control programmes cannot be evaluated in short term or by using crude morbidity statistics.

Age Factors↗