A long-term study on vector abundance & seasonal prevalence in relation to the occurrence of Japanese encephalitis in Gorakhpur district, Uttar Pradesh.

BACKGROUND & OBJECTIVES: Japanese encephalitis (JE) virus is an important cause of viral encephalitis in Gorakhpur district, UP. The area has been experiencing outbreaks of JE since 1978. No in-depth longitudinal studies have been carried out on the mosquito species, particularly JE vectors prevailing in the area. Entomological studies were carried out in the district in order to determine the species composition, relative abundance and seasonal prevalence of mosquitoes in relation to the incidence of JE. METHODS: Three JE affected villages were selected as study sites. Weekly visits were made to each village and mosquito collections were made in and around the pig enclosures and cattle sheds with the help of mouth aspirators, aided by flash lights at dusk. RESULTS: The overall mosquito population showed a bimodal pattern with short and tall peaks during March and September respectively. Based on the elevated density and infection with JE virus, Culex tritaeniorhynchus has been considered responsible for causing epidemics in the area. Cx. pseudovishnui, Cx. whitmorei, Cx. gelidus, Cx. epidesmus, Anopheles subpictus, An. peditaeniatus and Mansonia uniformis are suspected to have played some role in the epidemiology of JE in the region. JE cases were reported between August and November with the peak in October when the vectors population, particularly Cx. tritaeniorhynchus was on the decline. INTERPRETATION & CONCLUSION: The results of the study indicate that Cx. tritaeniorhynchus, the most likely vector of JE together with other known vector species remained more active during the period of paddy cultivation. Integrated antilarval measures before the beginning of paddy irrigation may check the breeding of JE vectors in the paddy fields. It may prove beneficial in reducing the vector population during the JE transmission season.

Total energy expenditure & physical activity level in chronically energy deficient Indian males measured by the doubly labelled water technique.

Total energy expenditure (TEE) and basal metabolic rate (BMR) in the free-living state were measured in healthy south Indians, by the doubly labelled water (DLW) method. From these measurements, estimates of physical activity level (PAL) could be calculated. A total of 18 subjects were studied in 3 groups of 6 subjects each: Group I (urban controls), Group II (urban slum, chronically undernourished) and Group III (rural). The urban slum recruits were chronically energy deficient (CED), and had a low BMI (average 17.0 kg/m2), while the rural subjects had an average BMI of 18.1 kg/m2. The TEE measured by the doubly labelled water technique was 11.2, 7.1 and 12.2 MJ/day for Groups I, II and III respectively. The TEE was significantly lower in the urban CED group as obtained by the one way ANOVA. The estimates of TEE by the DLW technique were compared with estimates made by whole body calorimetry, in the urban groups of subjects. The TEE obtained by calorimetry was 10.3 +/- 1.6 and 7.3 +/- 0.2 MJ/day in Groups I and II respectively. There were no significant differences between the TEE measured by the two methods, in both the groups. The two methods also correlated well, and the mean difference between the methods, in both groups was -0.5 +/- 1.1 MJ/day, which was about 6 per cent of the value of TEE measured by the DLW method. The calculated PAL (by using TEE measured by DLW/BMR) was 1.79, 1.54 and 1.90 for Groups I, II and III respectively. The results showed that the activity of chronically energy deficient subjects, in urban slums, was reduced, and that this may be their method of conserving energy to maintain a stable body weight. Rural males had a high activity level, even though they had a low BMI.

Diet induced thermogenesis with oral & intravenous feeding in chronically undernourished human subjects.

The parasympathetic nervous system (PNS) has been shown to be important in the mediation of diet induced thermogenesis (DIT). Chronically energy deficient (CED) subjects have a high resting parasympathetic tone, which could lead to a greater than expected DIT. DIT was studied in chronically energy deficient adult men and healthy age-matched volunteers (6 controls, 7 CED subjects) with an isocaloric (600 kcal) meal given by the oral and intravenous (i.v.) routes on two consecutive days, on a crossover basis. The resting metabolic rate (RMR) and the DIT were measured over 6 h, along with cardiovascular, biochemical and anthropometric parameters. Anthropometrically (height, weight, fat free mass, body mass index, mid upper arm circumference and sum of skinfolds), the CED group differed significantly from the well-nourished control group. There were no significant differences between the two groups in the basal state for metabolic (RMR, oxygen consumption, respiratory quotient), cardiovascular [blood pressure (BP), heart rate, cardiac output], and biochemical (plasma glucose, insulin and norepinephrine) parameters. The CED group had a significantly higher DIT response for both meal types when compared to the controls, when expressed as an absolute value and as a percentage response. However, the response was not significant when corrected for the meal size and body weight. There were also no significant differences between the two meal types in each group for the metabolic, cardiovascular and biochemical parameters during the DIT period, although, in general, the oral meal gave a larger DIT response compared to the i.v. meal. Both groups predominantly oxidised fat during the fasted stage and switched to carbohydrate oxidation when fed. It appears that, the previously demonstrated higher tone in the PNS, does not make a significant contribution to the thermic response of a meal in these subjects.

Metabolic responses to repeated infusions of identical doses of norepinephrine in chronically energy deficient human subjects.

The physiological effects of three 30 min infusions of identical doses of norepinephrine (0.15 microgram/kg FFM/min) separated by 60 min intervals were assessed in well nourished (WN; n = 6) and chronically energy deficient (CED; n = 6) subjects. Each subject also underwent control, vehicle infusions with 0.9 per cent saline on a separate day. Oxygen consumption (VO2) was significantly higher during the third infusion of NE as compared to the first in both groups. This increment in VO2 occurred despite similar plasma peak NE levels in both infusions. Increments in plasma glucose and free fatty acids were also similar during the first and third infusions. The study demonstrates that thermogenic potentiation which we had earlier demonstrated in WN subjects, occurs in CED subjects as well. Thermogenic potentiation is not associated with altered plasma NE kinetics or mobilisation of substrates.

Validation of expedient methods for measuring body composition in Indian adults.

The body composition of 99 men and 89 women from south India was estimated using hydrodensitometry, bioelectrical impedance and skinfold thickness. Comparisons of the hydrodensitometry (reference method) and skinfold methods showed that there were no significant differences between the methods, for estimates of fat free mass (FFM) and per cent fat. The mean difference between the estimates FFM (bias), from skinfold measurement and hydrodensitometry was small for both groups (+0.16 +/- 1.09 kg in men and +0.67 +/- 0.9 kg in women). The same trend was observed in per cent fat estimates (-0.37 +/- 2.04 in men and -1.49 +/- 2.28 in women), showing that the skinfold method can be used as an accurate and expedient method to determine body composition. The bioelectrical impedance method obtained a significantly lower FFM and higher body fat than the reference (hydrodensitometry) method. This could have been due to the use of an inappropriate equation derived from Western population studies. Hence, a new predictive equation, for the measurement of FFM by the bioelectrical impedance method was derived for this population, using the variables of height2/impedance and FFM measured by underwater weighing. The new equation for the bioelectrical impedance method then gave values of body composition which compared well (0.26 +/- 2.32 kg) in men and (0.36 +/- 2.49 kg) in women with the hydrodensitometry method.

Measurement of total energy expenditure by the doubly labelled water technique in free living Indians in Bangalore city.

Doubly labelled (2H2(18)O) water was used to determine the daily total energy expenditure (TEE) in the free living state of 6 adult, healthy, weight stable, male volunteers over a period of 21 days. The body weights of the subjects ranged from 42.3-70.4 kg. Isotope pool sizes and elimination rates were calculated from 18O and 2H enrichments in basal and daily (21 days) post dose urine samples using the multipoint slope intercept method after corrections for isotope fractionation. The physical activity level (PAL) of the subjects was also measured during the experiment as the ratio of measured TEE to measured basal metabolic rate (BMR). Simultaneous prediction of the total energy expenditure was also carried out by combining the measurements of BMR by indirect calorimetry, and daily physical activity level by 7 day recall. TEE calculated by the isotopic technique was 9.35 +/- 2.00 MJ/day, with an inter individual variation of 21.4 per cent. The measured BMRs in the subjects along with PALs obtained by recall, gave a total daily energy expenditure of 8.66 +/- 2.20 MJ/day with an inter individual variation of 25.4 per cent. The average BMR was 5.59 +/- 0.99 MJ/day and the average PAL (by recall) was 1.54 +/- 0.12. The inter individual variation of the BMR was 17.7 per cent and that of the recalled PAL was 7.9 per cent; the latter increased to 12.2 per cent when the PAL was calculated from the ratio of the measured TEE to the BMR. There was no significant differences between the methods (isotopic and predicted by BMR), although, the TEE obtained by the isotopic method was higher, by about 0.7 MJ/day, or 7.9 per cent, than the TEE predicted by BMR.

Thermal, cardiovascular & thermogenic responses to mild cold exposure in chronically energy deficient human subjects.

Thirteen young, male adults were investigated for thermal, cardiovascular and metabolic responses to truncal cooling for 40 min. The subjects were divided into two groups [well nourished controls (WN) and chronically energy deficient (CED)] on the basis of anthropometry and socio-economic status. The CED group had significantly greater reductions in peripheral forearm blood flow and surface finger tip temperatures on exposure to cold when compared to the well nourished controls. The CED group also showed a significant rise in oxygen consumption (3.4%), while no thermogenic response was observed in the WN controls. There was no fall in deep body temperature in either group. The study suggests that chronically energy deficient subjects thermoregulate appropriately on exposure to mild cold. The deficiency in insulative body fat is made up for by evoking greater peripheral vasoconstrictor responses as well as thermogenic mechanisms. The study suggests that on exposure to cold, thermoregulation takes precedence over energy conservation in chronically energy deficient subjects.

Exercise induced changes in the energy expenditure of female Wistar rats.

Changes in body weight and energy expenditure following exercise training was assessed in female Wistar rats. Rats were trained to swim in a tank filled with water for 2 hr everyday, 6 days a week. Changes in energy intake and body weight were recorded. The resting metabolic rate (RMR) was measured by indirect calorimetry and the capacity for non shivering thermogenesis (NST) was determined by measuring the stimulated oxygen consumption following a sc injection of norepinephrine (250 micrograms/kgbw). The RMR of exercised rats was 14% higher and the capacity for NST was 22% higher than that of sedentary rats. Energy intake of the exercised rats increased significantly while the body weights were maintained at levels comparable to that of the sedentary rats. Results indicate that body weight regulation is achieved by increasing food intake in response to the increased energy expenditure due to forced exercise as well as the stimulatory effect of exercise on RMR and NST.

Metabolic responses to episodes of partial dietary restriction in undernourished Wistar rats.

Wistar rat pups raised in large litters (LL) and small litters (SL) prior to weaning had access to ad libitum dietary intakes up to the age of 90 days. At 90 and again at 180 days they were partially diet restricted for a period of 15 days. Body weights, resting metabolic rates (RMR) and capacity for nonshivering thermogenesis (NST) was evaluated prior to, during and after the period of energy restriction. Responses were compared with 180 day rats from both groups who had been diet restricted for the first time at 180 days. Body weight losses were greater in the latter group. Groups of rats exposed to dietary restriction once, had higher body weights than rats of identical ages who had not been restricted. RMR decreased in all groups during restriction. However, reductions in NST were seen only in nutritionally deprived animals and in well-nourished controls who were partially restricted once. Changes in NST contribute to metabolic efficiency seen during episodic dietary restriction.

First isolation of Japanese encephalitis virus from the mosquito, Culex tritaeniorhynchus Giles, 1901 (Diptera: Culicidae) in Gorakhpur district, Uttar Pradesh.

A strain of Japanese encephalitis (JE) virus has been isolated from a pool of female mosquitoes of C. tritaeniorhynchus, using C. bitaeniorhynchus cell line. This is the first report of JE virus isolation from mosquitoes in Gorakhpur district of Uttar Pradesh, north India.

Nutritional assessment of marginally nourished surgical patients.

BACKGROUND. Anthropometric indices are known to be good indicators of nutritional status in the long term. However, there are conflicting reports about their effectiveness in short term assessments. METHODS. In 45 patients undergoing elective operations, the mid-arm circumference, biceps and triceps skin fold thickness and arm muscle area were measured. These were compared with haematological indices of nutritional status such as serum albumin, total protein and haemoglobin. The patients were divided into two groups based on their body mass index (< or > 18.5) or weight (< or > 52 kg). In another 10 patients, anthropometric and blood indices were studied pre- and postoperatively along with changes in body composition. RESULTS. When patients were grouped according to weight or body mass index, the anthropometric indices studied showed significant differences between the two groups, i.e. weight < 52 kg v. > 52 kg (mid-arm circumference: 22 +/- 3.3 cm v. 10 +/- 1.8 cm, p < 0.01; triceps skin fold thickness: 5.6 +/- 1.4 mm v. 10 +/- 4.9 mm, p < 0.01) although there were no differences in the blood indices. The 10 patients studied longitudinally were on energy-deficient intakes in the first postoperative week and lost lean tissue and body fat (-43 g, -33 g and -19 g protein and -78 g, -88 g and -97 g fat on postoperative days 1, 4 and 8 respectively). There was a variable response in terms of weight and body water. The measured anthropometric indices, however, showed no significant differences. CONCLUSIONS. Our results suggest that anthropometric indices are useful measures of nutritional status on a cross-sectional basis, whereas blood indices are not. Weight changes and anthropometric indices are not reliable guides to the short term nutritional course after an operation.

Superficial thermal gradients during mild body cooling and its relationship to forearm blood flow.

Forearm and fingertip temperature gradients were related to simultaneously measured forearm blood flow in eleven adult subjects at rest and during a mild cold stimulus. The change in temperature gradients were converted into a percentage change of the potential capacity for heat exchange and this was found to correlate well (r = 0.73: P < 0.001) with the absolute reduction in forearm blood flow.

Immediate heart rate responses to head-up tilt in healthy human subjects: response characteristics and variability.

Eight healthy adult males underwent three 70* head-up tilts within a nine day period. Immediate heart rate responses were monitored for 30 beats following completion of change to upright posture. The pooled data demonstrates a clearly demarcated bimodal heart rate response with a rise in heart rate by the 20th beat and a subsequent fall by the 30th beat. There is a secondary rise in heart rate with continuation of the tilted position. The bimodal response is at variance with several earlier reports. There is a large variability in the immediate heart rate responses, both between subjects of a homogeneous group and within subjects with repeated measurements. The large variability precludes the use of the immediate heart rate responses to passive tilting in autonomic testing.

Characteristics of norepinephrine stimulated thermogenesis in undernourished subjects.

Thermoregulatory thermogenesis was evaluated in chronically undernourished subjects as well as normally nourished controls by 60 min infusions of norepinephrine at a calculated dose of 0·15 μg/kg fat free mass/min. There was a significant (P<0·05) reduction in the thermogenic response to norepinephrine in the undernourished labourers. When the characteristics of response were evaluated, the baseline and peak responses were comparable in both groups. However, the steepness of the response was greater (P<0·05) in the undernourished subjects. The time to register a threshold response of 5 ml per min increase in oxygen consumption over the baseline after the start of infusion was longer in undernourished (about 20 min) as compared to the controls (about 10 min). It appears that, while the undernourished subjects have a reduced thermogenic component in their energy output, their peak capacity or potential for regulatory thermogenesis is the same as that in control subjects, since their thermogenic response has a greater slope. It is possible that chronically undernourished subjects may have a suppressed response over shorter periods of stimulation (less than 20 min), that is, before steady state thermogenic responses are achieved.

City studies on nutrition: Bangalore, India.

The size of urban population in developing Asian countries grows at a faster rate than in the developed West. Urban cities in India are being crushed by the onslaught of population growth, migration of rural poor and industrialization, the urbanization in turn inducing social and economic changes. During the decade 1972-81, India's population grew by 25%, urban population by over 40% and that of Bangalore city by 76%. The 1991 Census records the population of Bangalore city at 4.1 million, though the decennial growth rate seems to have begun to decline. The current sex ratio is 900 females to 1000 males with nearly 50% of the population literate and the density of population at 2200 per km2. With the rapidly expanding "conurbation" (continuous urbanization), the number of slum settlements have increased with Bangalore having recorded the highest annual growth rate of 27.4% in its slum population accounting for more than 10% of the share of its population in the slums within the corporation limits. 29% of the population in urban areas in the State is under the poverty line and the percentage under the poverty line may be higher in the city. In this situation the nutrition of the mother and child is most vulnerable. The incidence of low birth weight recorded in a Government Hospital in Bangalore was between 30-40% and the IMR at 47/1000 births. Incidence of child mortality was 5% for children under 1 year and 3% for preschool children. The percent distribution of PEM in preschool children was 41, 31 and 1 for Gomez Grades I, II and III respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Entomological investigations during outbreaks of dengue fever in certain villages in Maharashtra state.

Outbreaks of dengue (DEN) fever are reported from 22 villages in five districts in the state of Maharashtra. DEN viral antigen was detected by indirect immunofluorescence test in 34 of 375 female Aedes aegypti mosquitoes collected from 8 villages. DEN types 2 and 3 were identified among the 16 strains that were isolated. None of the 64 male mosquitoes showed the presence of viral antigen; 281 males and 323 females reared from field collected larvae were also found negative. Indoor spraying of DDT in the affected villages produced a drastic reduction in Ae. aegypti catches. No viral antigen was detected in mosquitoes caught subsequent to the spray. With the introduction of water supply through taps, which is often inadequate, people are compelled to store water for domestic purposes, which favours an increase in Ae. aegypti breeding. In view of changing rural ecology associated with the development process, continued surveillance of the spread of Ae. aegypti as well as the diseases borne by this vector are recommended.

The impact of early undernutrition on voluntary food consumption in later life of rats.

Food consumption patterns were studied during ad-libitum feeding of rats undernourished for 21 or 60 days after birth. Rats undernourished for 21 days consumed less food than the controls on a whole animal basis. But the food intake was higher during the early part of ad-libitum feeding when expressed on a unit body weight or metabolic body weight basis, and subsequently became comparable to that of the controls. Male rats undernourished for 60 days showed either comparable (for the whole animal) or higher (in other terms) food consumption, whereas the female rats undernourished for 60 days consumed more food at the beginning of ad-libitum feeding but less food during the latter part, when compared to their respective controls. The results thus indicate that no single mechanism can completely explain the food intake of undernourished rats during nutritional rehabilitation.