Biomedical subjects

K Krishnamoorthy

Publications and source records attributed to K Krishnamoorthy.

At least 37 records · Page 2Linked to original sources

PubMed1994

Aquatic vegetation and their natural hospitability to the immatures of Mansonia mosquitos, the vectors of Brugia malayi in Shertallai, Kerala, India.

Prevalence of various aquatic vegetation and their role in supporting vector breeding were studied by drawing plant samples from natural fresh water habitats in Shertallai region which is endemic for Brugia malayi. As many as 30 aquatic plant species were identified in addition to the most abundant and preferred host plants such as Pistia stratiotes, Salvinia molesta and Eichhornia crassipes which are of major concern due to their contribution for vector proliferation. Fallow lands and paddy fields recorded relatively a higher number of plant species. Natural breeding of Mansonia, the vector mosquitos was observed in 16 of them. Using the data on the prevalence, proportion of samples positive for Mansonia breeding and immature density, two indices viz, natural hospitability Index (NH) and Mansonia host plant Index (MHI) were developed for each plant species. Ranking of these plants in relation to Mansonia breeding was done based on these indices. Monochoria vaginalis has been identified to be one of the most important auxiliary host plant. Three grasses viz, Hygrorhiza aristata, Sacciolepis interrupta and Leersia hexandra were found to support all the three species of Mansonia viz, Ma. annulifera, Ma. uniformis and Ma. indiana with considerable immature density. The inclusion of these plants for weed/vector control is emphasized.

Animals↗

PubMed1992

Effectiveness of slow release formulations of fenthion (Baytex) in the control of Mansonia breeding in polluted pond habitats.

Effectiveness of two types of granular formulations of fenthion (Baytex) was evaluated in controlling the breeding of Mansonia mosquitos in polluted pond habitats. Calcium carbonate and sand granular formulations, when applied at 2.50 g/m2 surface area with an average depth of 0.5 m were found to be effective in keeping the habitats completely free from Mansonia breeding for 14 days and 18 days respectively. Release of insecticide was slow and the effective duration of control after a single application was relatively longer in the sand formulation when compared to the calcium carbonate formulation. Single application of calcium carbonate and sand granular formulations of fenthion could effectively prevent Mansonia adult emergence for 23 and 30 days, respectively in polluted pond habitats, without causing any adverse effect on non-target insects.

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

Neonatal herpes simplex meningoencephalitis: EEG investigations and clinical correlates.

We studied the sequential EEGs of 15 neonatal herpes simplex virus meningoencephalitis (NHSV-ME) patients and correlated them with corresponding clinical and laboratory findings. During days 1 to 4 of the illness, 8 had EEGs. All but 1 had abnormal tracings and 3 (38%) showed the multifocal periodic pattern (MPP). Three had an early abnormal EEG at a time when their cranial CT/ultrasound studies were normal. During days 5 to 11, 13 had EEGs: all were abnormal and 3 showed the MPP. After day 11, EEGs (available on 10) showed a very low voltage background in 9, and only 1 had normal EEG and development. During 1 year in which 1 patient with NHSV-ME was observed, we noted that 9/324 (2.8%) of neonates with other CNS conditions manifested the MPP. All, however, had CSF findings that distinguished them from herpes cases. We conclude that: (1) In patients with suspected NHSV-ME, EEG is a sensitive test that is superior to radiologic procedures in detecting early cerebral involvement. Most of the early EEGs show nonspecific background and paroxysmal abnormalities. (2) In the presence of inflammatory CSF, the MPP, an otherwise nonspecific finding, is highly suggestive of NHSV-ME. (3) Sequential EEGs may be important in the follow-up of neonates with NHSV-ME.

Electroencephalography↗

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

Clinical manifestations in malayan filariasis infection with special reference to lymphoedema grading.

In a door-to-door survey in Shertallai area of Kerala state in southern India, 7,766 persons were examined for clinical manifestations of filariasis. The prevalence of disease was 9.85 per cent and chronic persistent oedema (grade-II) was the predominant clinical presentation in both sexes. There was no significant difference in the age prevalence of disease between the sexes. Incidence of episodic filarial fever was higher (4.73/1000) compared to other manifestations (2.49/1000) in children aged 5-15 yr and hence this may be an useful indicator of the degree of occurrence of fresh cases of clinical filariasis. Classification of patients with lymphoedema into three grades showed that 1.65 per cent of those examined had developed lymphoedema within 6 months. Persistence of oedema (grade II) for prolonged period (13.64 +/- 1.17 yr) without skin changes indicated that the development of elephantiasis is a slow process. The clinical picture of malayan filariasis is similar to that reported elsewhere in the world except for the rarity of abscess formation is inguinal area.

Adolescent↗

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↗

PubMed1987

Respiratory complications in low-birth-weight infants who received phenobarbital.

We compared the ventilatory requirements of 127 infants who received phenobarbital for five days with those of 111 infants who received placebo. All infants were intubated, weighted less than 1750 g at birth, and survived the first ten days of life. Those infants who received phenobarbital did not require ventilatory assistance for more days than did placebo receivers. However, a pneumothorax or pulmonary interstitial emphysema was more likely to develop in infants who received phenobarbital than in infants who received placebo, even when adjustment was made for the presence of subependymal-intraventricular hemorrhage. We believe this is the first report of this relationship and recommend additional studies to test the hypothesis that phenobarbital contributes to the occurrence/recognition of pneumothorax or pulmonary interstitial emphysema in very-low-birth-weight infants if phenobarbital continues to be used routinely as prophylaxis or treatment.

Cerebral Hemorrhage↗

PubMed1986

Population movement and malaria persistence in Rameswaram Island.

The role of population movement on the persistent transmission of malaria in Rameswaram Island was studied. Majority of the inhabitants of the island are fishermen, who engage in perennial fishing. They move from one coastal place to the other for fishing and stay in temporary camps depending on season and fish availability. Such seasonal fishing camps attract fishermen from the mainland coastal villages also. The parasitological and entomological studies carried out in these places reveal that some of the camps are highly vulnerable to the movement of individuals with malaria infection and highly receptive. Rameswaram being a holy place, receives pilgrims from all over India and Nepal. Plasmodium falciparum cases recorded from the pilgrims of North India indicate the danger of the possible introduction of chloroquine-resistant parasite in the island. Also, a large number of passengers in transit from various countries, many of which are at risk of malaria transmission, stay in the island before or after visiting Sri Lanka. Such population movements being a continuous and regular feature are significant and result in failures in the operational programmes.

Anopheles↗

PubMed1986