The Long-term Value of Bariatric Surgery Interventions for American Adults With Type 2 Diabetes Mellitus

BACKGROUND

Bariatric surgery can cause type 2 diabetes (diabetes) remission for individuals with comorbid obesity, yet utilization is <1%. Surgery eligibility is currently limited to body mass index (BMI) ≥35 kg/m 2 , though the American Diabetes Association recommends expansion to BMI ≥30 kg/m 2 .

OBJECTIVE

We estimate the individual-level net social value benefits of diabetes remission through bariatric surgery and compare the population-level effects of expanding eligibility alone versus improving utilization for currently eligible individuals.

METHODS

Using microsimulation, we quantified the net social value (difference in lifetime health/economic benefits and costs) of bariatric surgery-related diabetes remission for Americans with obesity and diabetes. We compared projected lifetime surgical outcomes to conventional management at individual and population levels for current utilization (1%) and eligibility (BMI ≥35 kg/m 2 ) and expansions of both (>1%, and BMI ≥30 kg/m 2 ).

RESULTS

The per capita net social value of bariatric surgery-related diabetes remission was $264,670 (95% confidence interval: $234,527-294,814) under current and $227,114 (95% confidence interval: $205,300-248,928) under expanded eligibility, an 11.1% and 9.16% improvement over conventional management. Quality-adjusted life expectancy represented the largest gains (current: $194,706; expanded: $169,002); followed by earnings ($51,395 and $46,466), and medical savings ($41,769 and $34,866) balanced against the surgery cost ($23,200). Doubling surgical utilization for currently eligible patients provides higher population gains ($34.9B) than only expanding eligibility at current utilization ($29.0B).

CONCLUSIONS

Diabetes remission following bariatric surgery improves healthy life expectancy and provides net social benefit despite high procedural costs. Per capita benefits appear greater among currently eligible individuals. Therefore, policies that increase utilization may produce larger societal value than expanding eligibility criteria alone.

O021 Evaluating the impact of neurosurgical rotation experience in Africa on the interest and perception of medical students towards a career in neurosurgery: a continental, multi-centre, cross-sectional study

Introduction

Africa has the second-highest neurosurgical workforce deficit globally, and many medical students in Africa lack exposure to the field. This study aims to assess the impact of a neurosurgical rotation during medical school in shaping the perception and interest of students towards a career in neurosurgery.

Methods

This is a continental, multi-centre, cross-sectional study. A Google Form e-survey was disseminated to African clinical medical students between February 21st and March 20th, 2021. Data was analysed using descriptive statistics and adjusted logistic regression modelling.

Results

Data was received from 539 students in 30 African countries (n=30/54, 55.6%). The majority of participants were male (n=289/539, 53.6%) and were from Kenya (n=83/539, 15.4%). Most students had undertaken a clinical neurosurgery rotation (n=278/539, 51.6%); the majority reported a rotation length of four weeks or less (n=181/278, 65.1%). Students with clinical experience were less likely to pursue the specialty (p=0.02) and had a stronger perception that it is more difficult for women to pursue neurosurgery (p=0.0001) when compared to those without clinical experience. However, after adjusting for other factors, students with greater than four weeks of neurosurgical exposure were more likely to express a career interest in neurosurgery (odds ratio [OR]=1.75, p&lt;0.04) and men were more likely to express interest in a neurosurgical career compared to women (OR=3.22, p&lt;0.001).

Conclusion

Our findings support standardised, continent-wide, curriculum development, and advocacy supporting improved gender inclusivity in education and policy-making to improve the quality of neurosurgical exposure during medical school and tackle the workforce deficit across Africa.

Take-home message

A continent-wide, standardised curriculum guide to neurosurgical rotations, and advocacy for gender inclusivity in education and policy-making efforts across the African continent is required to shape the perception and interest of medical students towards a career in neurosurgery.

Quantifying the Value of Prevention: A Survey of Public Health Departments' Quantitative and Economic Modeling Capacity

OBJECTIVE

To improve the understanding of local health departments' (LHDs') capacity for and perceived barriers to using quantitative/economic modeling information to inform policy and program decisions.

DESIGN

We developed, tested, and deployed a novel survey to examine this topic.

SETTING

The study's sample frame included the 200 largest LHDs in terms of size of population served plus all other accredited LHDs (n = 67). The survey was e-mailed to 267 LHDs; respondents completed the survey online using SurveyMonkey.

PARTICIPANTS

Survey instructions requested that the survey be completed from the perspective of the entire health department by LHD's top executive or designate. A total of 63 unique LHDs responded (response rate: 39%).

MAIN OUTCOME MEASURE(S)

Capacity for quantitative and economic modeling was measured in 5 categories (routinely use information from models we create ourselves; routinely use information from models created by others; sometimes use information from models we create ourselves; sometimes use information from models created by others; never use information from modeling). Experience with modeling was measured in 4 categories (very, somewhat, not so, not at all).

RESULTS

Few (9.5%) respondents reported routinely using information from models, and most who did used information from models created by others. By contrast, respondents reported high levels of interest in using models and in gaining training in their use and the communication of model results. The most commonly reported barriers to modeling were funding and technical skills. Nearly all types of training topics listed were of interest.

CONCLUSIONS

Across a sample of large and/or accredited LHDs, we found modest levels of use of modeling coupled with strong interest in capacity for modeling and therefore highlight an opportunity for LHD growth and support. Both funding constraints and a lack of knowledge of how to develop and/or use modeling are barriers to desired progress around modeling. Educational or funding opportunities to promote capacity for and use of quantitative and economic modeling may catalyze use of modeling by public health practitioners.

Racial/ethnic disparities in specialty behavioral health care treatment patterns and expenditures among commercially insured patients in managed behavioral health care plans

OBJECTIVE

To document differences among racial/ethnic/gender groups in specialty behavioral health care (BH) utilization/expenditures; examine whether these differences are driven by probability vs intensity of treatment; and identify whether differences are explained by socioeconomic status (SES).

DATA SOURCE

The cohort consists of adults continuously enrolled in Optum plans with BH benefits during 2013.

STUDY DESIGN

We modeled each outcome using linear regressions among the entire sample stratified by race/ethnicity, language and gender. Then, we estimated logistic regressions of the probability that an enrollee had any spending/use in a given service category (service penetration) and linear regressions of spending/use among the user subpopulation (treatment intensity). Lastly, all analyses were rerun with SES controls.

DATA COLLECTION

This study links administrative data from a managed BH organization to a commercial marketing database.

PRINCIPAL FINDINGS

We found that in many cases, racial/ethnic minorities had lower specialty BH expenditures/utilization, relative to whites, primarily driven by differences in service penetration. Among women, relative to whites, Asian non-English speakers, Asian English speakers, Hispanic non-English speakers, Hispanic English speakers, and blacks had $106, $95, $90, $48, and $61 less in total expenditures. SES explained racial/ethnic differences in treatment intensity but not service penetration.

CONCLUSIONS

In this population, SES was not a major driver of racial/ethnic differences in specialty BH utilization. Future studies should explore the role of other factors not studied here, such as stigma, cultural competence, and geography.

Access to Care and Health Outcomes Among Women Veterans Using Veterans Administration Health Care: Association With Food Insufficiency

BACKGROUND

Food insecurity has been associated with worse health outcomes in the civilian population. Male veterans of the Gulf Wars have been shown to have a higher prevalence of food insecurity than similarly situated civilians. Women veterans have more risk factors for food insecurity, relative to male veterans, yet little is known about the prevalence of food insecurity in this cohort.

METHODS

We used the Women Veterans' Health Utilization and Experience Survey for this analysis. Our study population consisted of women veterans who had at least three primary care or women's health visits to 1 of 12 Veteran's Health Administration health care facilities from December 2013 to November 2014. Multiple logistic regression was used to examine the relationship between food insufficiency (an inadequate amount of food intake owing to a lack of money or resources), delayed/missed care, anxiety, depression, and self-reported fair to poor health, controlling for race/ethnicity, marital status, and employment status.

RESULTS

The prevalence of food insufficiency among women veterans was 27.6%. Being food insufficient was associated with 16.4, 15.4, 14.9, and 12.1 percentage point increases in the probability of delayed/missed care, screening positive for anxiety, screening positive for depression, and reporting fair to poor health, respectively (p < .05).

CONCLUSIONS

The prevalence of food insufficiency in this cohort was associated with delayed access to health care and worse health outcomes. Interventions addressing Veterans Administration access and health outcomes will need to examine the potential role of food insufficiency.

The Impact of Exceeding TANF Time Limits on the Access to Healthcare of Low-Income Mothers

The objective of this article is to estimate the relationship of exceeding Temporary Assistance for Needy Families (TANF) time limits, with health insurance, healthcare, and health outcomes. The authors use Heckman selection models that exploit variability in state time-limit duration and timing of policy implementation as identifying exclusion restrictions to adjust the effect estimates of exceeding time limits for possible correlations between the probability of exceeding time limits and unobservable factors influencing the outcomes. The authors find that exceeding time limits decreases the predicted probability of Medicaid coverage, increases the predicted probability of being uninsured, and decreases the predicted probability of annual medical provider contact.

Direct and early detection of Mycobacterium tuberculosis complex and rifampicin resistance from sputum smears

SETTING

Four district DOTS centres in Sikkim, India.

OBJECTIVE

Direct and early detection of Mycobacterium tuberculosis complex and rifampicin (RMP) susceptibility using the INNO-LiPA Rif.TB assay.

DESIGN

DNA was extracted from 44 inactivated acid-fast bacilli-positive sputum slides using the Gen Elute bacterial genomic DNA kit. Eluted DNA were ethanol precipitated. The LiPA kit detected RMP susceptibility by detection of mutation in the 81 base pair (bp) rpoB gene. Culture of sputum from the same person was used for drug susceptibility testing for RMP using the proportion method.

RESULTS

Amplification of 88.6% (39 slides) was achieved from DNA extracted using kits (66.7% for 1+, 81.8% for 2+ and 100% for 3+ slides). Hybridisation using the LiPA kit was applied to 31 amplified products. There was a concordance of 96.8% (24 RMP-resistant and 6 RMP-susceptible samples) and discordance of 3.2% (one sample resistant using the proportion method and susceptible on LiPA) between LiPA and the proportion method.

CONCLUSION

LiPA proved useful on DNA extracted from smear-positive slides. Appropriate treatment regimen could be decided early. Slide smear preparation could replace sputum transport in cetylpyridinium chloride, reducing biohazard and thereby controlling the transmission of multidrug-resistant tuberculosis in the community.

Anaemia & expression levels of CD35, CD55 & CD59 on red blood cells in Plasmodium falciparum malaria patients from India

BACKGROUND & OBJECTIVES

Severe anaemia in Plasmodium falciparum (Pf) associated malaria is a leading cause of death despite low levels of parasitaemia. In an effort to understand the pathogenesis of anaemia we studied expression level of RBC complement regulatory proteins, CR1 (CD35), CD55 and CD59 with haemoglobin status in a group of malaria cases from Assam, Goa and Chennai, and in healthy controls.

METHODS

Flowcytometry was used to study expression of CR1, CD55 and CD59 in 50 Pf cases and 30 normal healthy volunteers. Giemsa stained thick and thin blood films were used for microscopic detection and identification of malarial parasites and parasite count.

RESULTS

No correlation was found between degree of expression of RBC surface receptors CR1, CD55 and CD59 with haemoglobin level. However, expression of CD55 was less in malaria cases than in healthy controls.

INTERPRETATION & CONCLUSIONS

The present findings indicate that malaria infection changes the expression profile of complement regulatory protein CD55 irrespective of severity status of anaemia. Further studies are needed to explore the pathophysiology of anaemia in malaria cases in Assam where expression of RBC complement receptors appears to be low even in normal healthy population.

A randomized trial comparing the efficacy of four treatment regimens for uncomplicated falciparum malaria in Assam state, India

A four-arm drug sensitivity study compared chloroquine, sulfadoxine-pyrimethamine (SP), mefloquine and mefloquine-artesunate in Sonitpur and Karbi Anglong districts in Assam state, India. Two criteria were used to ascertain outcome: success of clinical treatment and parasitologic cure. In Sonitpur, at 14 days, there were 36/56 early and late treatment failures plus late parasitologic failures to chloroquine and 16/56 for SP. In Karbi Anglong, combined treatment failure at 14 days was 16/56 to chloroquine and 8/60 to SP. Mefloquine and mefloquine-artesunate demonstrated 93.9% and 93.6% sustained responses respectively at 42 days. High failure rates to both chloroquine and SP preclude the use of these drugs as first-line treatment for uncomplicated falciparum malaria in this region. A mefloquine-artesunate combination presents an effective alternative utilizing the currently recommended higher dose of mefloquine.

Hypertension in the native rural population of Assam

BACKGROUND

Recent studies have reported an increasing prevalence of hypertension in India. However, there are few epidemiological data with regard to the occurrence of hypertension in the native population of Assam.

METHODS

Three thousand one hundred and eighty individuals (1441 men and 1739 women), > or =30 years of age and from 25 villages of 5 districts in Assam were selected by the stratified random sampling method. They were interviewed and their blood pressure measured along with other anthropometric variables. Hypertension was defined according to the Sixth Report of the Joint National Committee on prevention, detection, evaluation and treatment of high blood pressure (JNC-VI).

RESULTS

The overall prevalence of hypertension was 33.3%. Among the patients with hypertension, 21.6% were aware of their illness. The determinants of hypertension were age, intake of extra salt in the diet, body mass index and waist-hip ratio (derived by multiple logistic regression analysis with backward elimination of non-significant factors). Multivariate analysis showed that females had a higher risk of hypertension than males.

CONCLUSION

The prevalence of hypertension in the native population of Assam is high. Implementation of an effective awareness programme with lifestyle modifications is necessary to control the cardiovascular disease burden in this population.

Cure and reinfection patterns of geohelminthic infections after treatment in communities inhabiting the tropical rainforest of Assam, India

Mass de-worming targeted at socio-economically poor communities can be considered as an option for communities living in the tropical forests of Assam who do not have access to safe drinking water and proper sanitation, and consequently have a higher risk of suffering from geohelminthic infection and associated morbidity. A random sample of 265 subjects was included in this study (134 males and 131 females). The chemotherapeutic regimen followed was a single dose of albendazole 400 mg. Stools samples were collected in 10% formol-saline for detection of infection before treatment. Post-treatment stool samples were collected 10 to 14 days after treatment to determine the cure rate. Stool samples were again collected 3 to 6 months post-treatment to study the rate of reinfection. Multiple logistic regression was used to find possible associations between age, sex and treatment failure. The chi-square test was used wherever appropriate. The cure rates for Ascaris lumbricoides, Trichuris trichiura and hookworms were 70.8%, 68.7% and 93.0%, respectively. Logistic regression revealed that age was associated with treatment failure in A. lumbricoides infection. Re-infection rates after 3 months of successful treatment were 19.6% for A. lumbricoides, 30.9% for T. trichiura and 11.3% for hookworms. Six months post-treatment, the prevalence of re-infection was highest with T. trichiura (43.6%); followed by A. lumbricoides (35.3%). The rate of reinfection with hookworms was lower (11.3%) six months post-treatment. The rates of re-infection with A. lumbricoides and T. trichiura was higher in children below 15 years of age, compared with adults. Hookworm reinfection was higher in the adult age group (15 to 39 years). The rates of new infection in previously uninfected subjects were lower compared with the rates for re-infection.

Differences in blood pressure level and hypertension in three ethnic groups of northeastern India

A cross sectional study on hypertension was done on 294 subjects aged 30 years and above. 150 households were selected randomly representing 50 households from each locality inhabited exclusively by the rural Mizos, indigenous rural Assamese and the tea-garden workers respectively, in the northeastern region of India. Blood pressure was measured by sphygmo-manometer in sitting posture. Anthro-pometric measurements were taken using standard procedure for measuring height, weight, waist and hip girth. Information on age, sex, ethnicity, literacy, alcohol intake, smoking pattern, physical activity, occupation, amount of salt consumption was collected using a standard and pre-tested questionnaire. Significant differences were observed in both the systolic and diastolic blood pressure levels among the three different ethnic groups selected for this study (p < 0.0001). Multiple regression analyses indicated that in Mizos, age, waist circumference and alcohol intake were independently associated with increase in systolic blood pressure whereas smoking was found to be negatively associated with systolic blood pressure (R2 = 0.391, p < 0.001). Factors, which were the best predictors of diastolic blood pressure, were age and body mass index [(kg/m2) (R2 = 0.227, p < 0.001)]. In the rural Assamese population, the best predictors of systolic blood pressure were age and waist circumference (R2 = 0.263, p = 0.018). For the diastolic blood pressure, age, alcohol intake and body mass index were important correlates (R2 = 0.131, p < 0.001). In the tea garden community, important predictors of systolic blood pressure were age, gender and marital status (R2 = 0.187, p < 0.001). On the other hand, age and alcohol intake were best predictors for diastolic blood pressure (R2 = 0.09, p < 0.001).

Hypertension and its risk factors in tea garden workers of Assam

BACKGROUND

Hypertension is emerging as a major public health problem in India. The diversity and heterogeneity of distribution of the population makes it difficult to arrive at the precise prevalence. In Assam, reports from hospitals in tea gardens reveal a high prevalence of hypertension among workers in tea gardens. However, no systematic study has been carried out in this population.

METHODS

We selected, by systematic sampling, 1015 individuals (512 men and 503 women) 30 years or more in age, who were interviewed and clinically examined for hypertension. Blood pressure of all the study participants was measured using a standardized technique. Crude and adjusted odds ratios were estimated by unconditional simple and multiple logistic regression analyses. Mantel-Haenszel chi2 analysis was also used to test for the association of potential risk factors with hypertension after controlling for co-variables in a stratified analysis. Risk factors considered for hypertension included age, gender, marital status, occupation, alcohol consumption (locally prepared), extra salt intake, smoking history, khaini (a form of tobacco quid containing a mixture of tobacco and lime) intake, body mass index and waist-hip ratio.

RESULTS

The overall prevalence of hypertension was 60.8%. Increasing age, consumption of locally prepared alcohol, intake of extra salt in food and beverages and the habit of taking khaini were found to increase the risk of hypertension. Multivariate logistic regression models showed that the independent determinants of hypertension were age, gender, consumption of locally prepared alcohol and intake of extra salt. Gender-specific and age-stratified analyses showed the association of increased risk with intake of khaini in women only, while consumption of locally prepared alcohol was an important risk factor for hypertension in both men and women.

CONCLUSION

The disease burden of hypertension among workers in tea gardens is large, despite the community not being obese. Interventions directed at these workers as well as studies to determine the reasons for the high prevalence of hypertension are required.

Transmission of bancroftian filariasis in tea agro-ecosystem of Assam, India

Tea industry is a labor intensive agro-industry and filariasis is mostly localized among the tea garden workers in Assam. The workers live inside the gardens in colonies. Studies conducted in two cosecutive years revealed that among the host seeking Culex quinquefasciatus average infection rate was 4.6% and with 2.1 larvae per mosquito. The overall prevalence of infective mosquitos was 0.8% with average L3 load of 2.0 per mosquito. The probability of infected mosquitos surviving to have complete development of filarial larvae (13 days) was 0.17. The expectation of infective life was 1.416 days for man biting Cx. quinquefasciatus and the estimated adult survival rate of was 87.6%. It has been estimated that a total of 22,569 mosquito bites were received/man/year in tea garden environment out of which 182 bites/man/year were infective (0.806%). The monthly biting rate varied from 310-4,758.5 bites per man (mean 1,846 +/- 1,389.7 SD). Monthly transmission index of W. bancrofti filaria showed two periods of transmission. In both the year no infection was detected during February and March and infection rate remained low up to May (average infection in April 0.72% and in May 0.48%).

Risk factors of malaria in the fringes of an evergreen monsoon forest of Arunachal Pradesh

BACKGROUND

The forested hilly and foothill regions of north-east India are highly endemic for malaria and have a distinct epidemiological pattern. Nearly half the reported cases of malaria are from these areas. A knowledge of the risk factors in this eco-geographic entity may be helpful in formulating a specific control strategy. Hence, we conducted a community-based epidemiological study in a hilly, forested terrain of Arunachal Pradesh and examined different socio-demographic factors to identify those predisposing to the occurrence of malaria, especially Plasmodium falciparum infection, in such areas.

METHODS

Four epidemiological surveys were carried out during 1997 in 7 villages located at the fringes of a forest (total population: 1177) under Nompong Primary Health Centre of Changlang district, Arunachal Pradesh. Blood slides were collected randomly from the inhabitants, irrespective of their fever status, ensuring at least 50% coverage. One hundred and thirty-four microscopically confirmed Plasmodium falciparum cases were identified and 536 controls were randomly selected from the list of uninfected inhabitants. Relevant socio-demographic information was obtained from both cases and controls. The data were analysed by simple and multiple logistic regression using the unconditional maximum likelihood method.

RESULTS

Factors which were found to be strongly associated with Plasmodium falciparum malaria on univariate analysis were age, ethnicity, village of residence and accessibility to the nearest health care facility. However, in multiple regression analysis, after controlling for the effects of confounding variables, the only risk factor identified was accessibility to the nearest health care facility (adjusted odds ratio: 4.5; 95% CI: 1.8-11.3; p < 0.0001 for those at a distance of 2-8 km and adjusted odds ratio: 11.1; 95% CI: 4.1-30.0; p < 0.0001 for those > 8 km away).

CONCLUSION

Distance, particularly non-motorable distance, from the place of residence to the nearest health care facility was a major risk factor for malaria in this hilly forested terrain. This indicates the need for special efforts to detect cases early and institute treatment promptly in such areas of the north-eastern region, so as to reduce the morbidity and mortality of malaria.

Prevalence of Trichuris trichiura in relation to socio-economic & behavioural determinants of exposure to infection in rural Assam

BACKGROUND & OBJECTIVES

Stunting, anaemia, and the poor level of mental development are known to be associated with Trichuris trichiura infections. However, no information is available on the socio-environmental predictors relevant to Trichuris infection in rural communities. Whilst geohelminthic infections per se is an inevitable consequence of poor personal hygiene and household sanitation, the importance of specific factors in the epidemiology of Trichuris infection have not been formally investigated. The objective of this study was to explore, quantify and study different socio-environmental risk factors and find out their possible interaction vis-a-vis T. trichiura infection.

METHODS

The study population consisted of 244 children (aged 15 yr and below) and 336 adults selected from 144 randomly selected households belonging to three villages of upper Assam. The prevalence rate ratio (PRR; = relative risk) and 95 per cent confidence interval (CI) were calculated. Univariate, multivariate analysis using Cox's proportional hazards regression assuming constant risk period and a tree-based risk factor analysis, were used.

RESULTS

In the overall multivariate model, open field defaecation, large family size, and three or more children in the household were found independently associated with Trichuris infection. Gender specific analysis revealed that in females the age was also independently associated with increased risk of infection whereas in males, earth flooring was the most significant risk factor independently associated with the risk of Trichuris infection. Tree-based risk factor analysis indicated interaction between defaecating habits of people and the source of drinking water.

INTERPRETATION & CONCLUSIONS

Installation of pit latrines (if not sanitary latrines) together with provision for safe drinking water and the construction of cement floors would probably reduce community prevalence of T. trichiura effectively.

Risk factors for cancer nasopharynx: a case-control study from Nagaland, India

BACKGROUND

A high incidence of nasopharyngeal carcinoma has been reported from Nagaland, though it is considered to be a rare neoplasm in India. No case-control study to identify the risk factors of cancer nasopharynx has been conducted in this region. This study was undertaken to identify dietary and environmental risk factors for nasopharyngeal carcinoma relevant to this region.

METHODS

A matched case-control study using neighbourhood controls was conducted. For each of the 47 cases identified, 2 apparently healthy neighbourhood controls were matched for age, sex and ethnicity. All information on dietary, environmental, social and demographic factors was collected. Univariate and multivariate logistic regression analysis using maximum likelihood method was used to analyse data.

RESULTS

Consumption of smoked meat was found to be the risk factor for nasopharyngeal carcinoma (adjusted odds ratio = 10.8; 95% CI 3.0-39.0). History of using herbal nasal medicine was also found to be associated with nasopharyngeal carcinoma (OR = 21.9, CI = 6.8-71.4). However, exposure to a smoky atmosphere, betel-nut chewing, use of smokeless tobacco products, smoking and drinking habits were not found to be associated with nasopharyngeal carcinoma.

CONCLUSION

This study reveals an association of nasopharyngeal carcinoma with consumption of smoked meat in Nagaland. The use of herbal nasal medicine seems to be an additional risk factor for nasopharyngeal carcinoma in Nagaland and needs further assessment.

Temporal variations in biting density and rhythm of Culex quinquefasciatus in tea agro-ecosystem of Assam, India

Temporal changes in the biting density and host-seeking periodicity of Culex quinquefasciatus, the vector of bancroftian filariasis, were studied for two years in the tea agro-ecosystem of Assam, India. Average biting density of the vector varied from 0.8/hour in December to 13.3/hour in March. Minimum temperature was found to have a limiting effect on the biting density of the vector mosquitos. Multiple regression analysis showed that the rainfall and minimum temperature were significant factors influencing biting density of this vector mosquito. The biting rhythm of Cx. quinquefasciatus was found to be nocturnal with two distinct peak periods of biting activity. The first peak was around 19.00 to 20.00 hours and the second peak period was around 22.00 to 23.00 hours. Biting activity however was seen throughout the night with declining trend as the night proceeded.

Larval ecology and mosquito fauna of upper Brahmaputra valley, northeast India

Ninety-one mosquito species in 15 genera were collected from 22 habitat types of Upper Brahmaputra valley in Assam and bordering areas of Arunachal Pradesh. Nineteen species have been recorded for the first time in Assam including seven first records from the northeast region and three first country records. Jaccard's coefficient was used to quantify the similarity between 13 different geographical localities surveyed on the basis of their mosquito fauna. Group average sorting (UPGMA) cluster analysis was used to find out relationship between Jonai, Dhemaji, Dibrugarh, Tinsukia and north Lakhimpur (study zones) on the basis of their mosquito community. Immatures of three malaria vectors incriminated from the northeast India, viz. Anopheles dirus, An. minimus and An. philippinensis were collected exclusively from forest areas. Fourteen potential vectors of Japanese encephalitis incriminated from elsewhere in India were collected during the study.

Incrimination of Schistosoma spindale as a causative agent of farmer's dermatitis in Assam with a note on liver pathology in mice

Cercarial dermatitis of paddy field workers in Assam is very common. However, it is not known which species of animal schistosomes, is its causative agent in Assam. Studies in two dermatitis affected villages of Dibrugarh district revealed that cercariae of Schistosoma spindale were involved in its aetiology. Indoplanorbis exustus was the only snail species found infected with apharyngeate brevifurcate schistosome cercarie. Experimental infection of the laboratory animals with the dermatitis causing schistosome cercariae revealed that duckling and chicken were refractory to infection. However, Swiss albino mice were successfully infected. The number of adult flukes per infected mice ranged from 6-321 (mean intensity = 68.1; S.D. = +/- 112.96). Histopathological study of infected mice liver revealed that there was mild inflammation of infected portal triads towards the presence of male flukes in the intra hepatic portal vessels. Kuppffer cells showed hyperplasia and contained large amounts of black pigment. No eggs or egg granulomas were detected in the liver parenchyma. There was no evidence of thrombophlebitis, septal fibrosis or pipe stem fibrosis.

Human distomatosis due to Fasciola hepatica infection in Assam, India

A seven year old girl in a rural area of Upper Assam was found to be infected with Fasciola hepatica. The girl gave history of eating watercress. Besides the presence of eggs in the stools, her liver was enlarged and tender. Liver function tests revealed hepato-biliary involvement with increase in serum AKP and ALT. Ultrasonography revealed presence of adult fluke in gall bladder, and a marginal thickening of gall bladder wall. However, the echo pattern of her liver parenchyma was normal. The case is reported for its public health significance and is a maiden report from north eastern India.

Biting behaviour and biting rhythm of potential Japanese encephalitis vectors in Assam

Studies on biting behaviour and biting cycles of medically important mosquitoes were carried out in Madhupur village and Tarajan tea estate of upper Assam. Collections were made off human baits outdoors and indoors and off cattle bait outdoors from August 1991 to July 1992. Human bait collections were performed using the 'stationary direct bait' technique. A total of 9,072 adult host seeking female mosquitoes representing 26 species and 5 genera were collected off baits of which 36.9% were collected off human baits and the rest from cattle. All mosquitoes were primarily zoophilic, although significant numbers were collected biting man outdoors. Biting preferences of important Japanese encephalitis (JE) vectors for man and cattle were studied using outdoor man:outdoor cattle ratio (attraction ratio = AR). Culex quinquefasciatus was attracted towards human baits the most (AR = 8.1:1), followed by Cx. bitaeniorhynchus (AR = 1.6:1) and Mansonia annulifera (AR = 1.3.1). The hourly biting activity of important JE vectors throughout the night on two bait types was also studied using three point moving averages. Hierarchical agglomerative cluster analysis was used to compare and classify mosquitoes on the basis of their similarity in biting rhythms.

Combined paresis and restriction of the extraocular muscles after orbital fracture: a study of 16 patients

Sixteen patients with combined paresis and restriction of extraocular muscle(s) orbital fracture repair were studied before and after in order to determine the clinical features and management of such patients. All 16 patients showed limited ductions of the involved eye in the field of action of the entrapped, paretic muscle and of the antagonist muscle after orbital fracture. Single extraocular muscles (13 patients) and two extraocular muscles (three patients) were demonstrated adjacent to the fracture site on orbital computed tomography (CT). In three patients prior to orbital surgery, a deviation in primary position was present. After fracture repair with release of the entrapped muscle in all patients, evidence of paresis of the muscle was demonstrated by underaction in its field of action and overaction in the field of its antagonist. There was a resultant manifest tropia or phoria in the primary position. In seven patients, the paresis gradually improved with no tropia and little diplopia in the functional fields of gaze. Three patients had minimal deviations and required no further treatment. Six patients with significant deviations required prisms (three patients) or strabismus surgery (three patients). The latter three patients had two muscles involved. Results of this study demonstrate that the ophthalmologist must appropriately diagnose patients with paresis and restriction of an extraocular muscle and counsel them that "new" diplopia may occur after orbital fracture repair and that this diplopia may require additional therapy.

Role of some environmental factors in modulating seasonal abundance of potential Japanese encephalitis vectors in Assam, India

Temporal changes in the abundance of host-seeking, potential Japanese encephalitis (JE) vector mosquitos and the role of some ecological factors that are modulating the abundance of vector mosquitos were studied. Vector surveillance was conducted for one year in 4 JE prone villages of Dibrugarh, Assam. Among potential JE vectors, the most abundant mosquito was Culex vishnui s.s. comprising about 22.32%. Maximum density of the mosquito was found during the month of April and another peak was observed in the month of September. The influence of meteorological factors on the abundance of JE vectors was found to vary from species to species. The final multiple regression equations (after variables were selected using STEPWISE procedure) consisted of a combination of linear, quadratic, cubic and interactive ecological variables and accounted for 25-98% of the variations in the abundance of JE vector mosquitos. Complex interactions among environmental factors, such as minimum and maximum temperature, rainfall and flood level are involved in modulating the seasonal abundance of mosquitos. A time lag is involved before a cause and effect relationship is established between environmental parameters (independent variables) and entomological variables (dependent variables). Inundation caused by flooding is favorable for mansonioid mosquito species whereas it has an adverse effect on non-mansonioid mosquito species.

Heterophyid eggs in human stool samples in Assam: first report for India

Two cases from a Muslim family in upper Assam were found to pass trematode eggs morphologically similar to the members of the family Heterophyidae Odhner, 1914. The eggs characteristically yellowish brown in colour, ovoid, have a thick shell and are operculate. They measured 31.5 +/- 2.0 um SD x 22.4 +/- 1.9 um SD with well developed miracidium. This is the first record of human heterophyid infection from India.

Paddy field dermatitis in Assam: a cercarial dermatitis

Rice field dermatitis is an occupational health problem in Assam. The afflicted paddy field workers develop exanthema on the exposed parts of their skin mainly legs and arms when they come in contact with water in rice fields. Itching sensations start after 30 minutes to 1 1/2 hours after initial exposure. After 6-12 hours there is intensely pruritic macular eruption and in a few cases secondary skin infection may also develop. The clinical course of the disease is suggestive of cercarial dermatitis. Numerous gastropod snails belonging to families Lymnaeidae, Bulinidae and Planorbidae were collected from paddy fields and were investigated for cercarial infection. It was found that planorbid snails were infected with animal schistosome cercariae. These cercariae were able to invade human skin and caused dermatitis in human volunteers after repeated exposure.