Natural vertical transmission of dengue viruses by Aedes aegypti in Chennai, Tamil Nadu, India

BACKGROUND & OBJECTIVE

Dengue viruses are spread and maintained in an Aedes aegypti-human- Ae. aegypti cycle in urban areas of the tropics. Dengue viruses are also maintained in nature by vertical transmission by Ae. aegypti. A study was undertaken in Chennai, a known endemic city in south India, to comprehend the natural vertical transmission dynamics in Ae. aegypti and to assess its epidemiological importance.

METHODS

Ae. aegypti males collected in resting and landing collections were tested for dengue virus infection by antigen-capture enzyme-linked immunosorbent assay (ELISA) and further examined by insect bioassay, Toxorhynchites splendens inoculation-indirect immunofluorescence technique (Toxo-IFA) using serotype-specific monoclonal antibodies (Mabs), if found positive by ELISA.

RESULTS

Of the 509 pools of Ae. aegypti males (n=5408) screened, 15 pools, collected in April, June- July, November-December in 2003 and March, May in 2004, were found positive for dengue virus infection and the minimum infection rate (MIR) among adult males was high in June 2003 (28.0/ 1000). Three positive pools could be serotyped as dengue-2 (2 pools) and dengue-3 (1 pool).

INTERPRETATION & CONCLUSION

Dengue virus isolations from wild caught males of Ae. aegypti indicate the occurrence of transovarial transmission. Vertical transmission was mainly observed in summer months when dengue infections in humans were low suggesting that dengue viruses adopt a novel strategy of surviving adverse climatic conditions.

Awareness of health personnel about lymphatic filariasis and mass drug administration in Kerala State

The mass drug administration programme to eliminate lymphatic filariasis with DEC in Kerala was started in 1997, extended to all the 11 endemic districts by 2005. Since the beginning of Mass drug Administration, the drug consumption rate was found to be not satisfactory. The reasons for noncompliance indicated that the community is not fully convinced about the programme. The knowledge of the medical and para medical workers is certainly a factor in the success of implementation of the programme and is vital. To ascertain the knowledge, a study was undertaken and found not satisfactory. Hence intensive training on all aspects of lymphatic filariasis and the Mass drug Administration programme to achieve the requisite drug consumption rate to meet the goal is needed.

Inducible nitric oxide synthase expression is upregulated in oral submucous fibrosis

OBJECTIVE

We tested the hypothesis that inducible nitric oxide synthase (iNOS) modulates angiogenesis in human models and this information could be extrapolated in elucidating the pathophysiology of oral submucous fibrosis (OSF). A hypothesis which looks inadequate, but is deep rooted in literature is the epithelial alteration ("atrophy") seen in OSF and the events that lead to its causation. This aspect was tried to be addressed and an alternative pathogenetic pathway for the disease is proposed.

MATERIALS AND METHODS

This immunohistochemical study sought to investigate the expression of iNOS in OSF samples (n=30) a using monospecific antibody (SC- 2050, Santa Cruz Biotechnology, Inc) to the protein and also to correlate it with different grades of epithelial dysplasia associated with the disease. Twenty (20) healthy adults acted as controls.

RESULTS

iNOS staining was not demonstrated in normal oral epithelium. In oral epithelial dysplasia, staining was seen in all cases (100%) in the basal layers of the epithelium and in 30% of cases it extended into the parabasal compartments as well. iNOS staining was uniformly positive in moderate dysplasia with an increase in intensity and distribution noted as the severity of dysplasia progressed. There were highly significant differences in overall positivity for iNOS in epithelium between cases and controls (Mann-Whitney U=11.000, Wilcoxon W=221.00, P=0.000). Significant comparisons were made of mild Vs moderate dysplasia (Mann-Whitney U=48.000, P=0.014)

CONCLUSIONS

This study supports our earlier morphological assessment (image analysis) of the nature of vascularity in OSF mucosa. The significant vasodilation noticed in these cases argues against the concept of ischemic atrophy of the epithelium. This observation of vascularity and iNOS expression helped to explain the vasodilation noticed (sinusoids) in this disease; NO being a net vasodilator. The mechanism of activation of iNOS in dysplasia is difficult to explain. The role of contingent paracrine-activating factors on keratinocytes and macrophages is discussed.

Vector control complements mass drug administration against bancroftian filariasis in Tirukoilur, India

OBJECTIVE

To determine the role of vector control in further decreasing the transmission of bancroftian filariasis achieved by mass drug administration and the long-term impact on filariometric indices.

METHODS

Three rounds of annual mass drug administration, with diethylcarbamazine and ivermectin, were complemented by vector control (mainly using polystyrene beads) in villages of Tirukoilur, south India, during 1995-99. Subsequently, drug administration is being carried out with diethylcarbamazine and albendazole or diethylcarbamazine alone. We evaluated the impact of mass drug administration used alone or in conjunction with vector control (from 1995 to 2005) on vector transmission indices (such as transmission intensity index, monthly biting rate, monthly transmission potential and annual transmission potential). We analysed data on filarial infection in the community to estimate the prevalence of microfilaraemia and antigenaemia using chi2 analysis and Fisher's exact test.

FINDINGS

Vector density greatly decreased in villages where vector control was used as an adjunct to mass drug administration and almost no infective mosquitoes were found in the small numbers still remaining. Filarial antigenaemia was low and continued to decrease significantly in the age group 15-25 years in villages receiving mass drug administration with vector control in contrast to villages receiving only mass drug administration.

CONCLUSION

The gains of mass drug administration were sustained only with the integration of vector control measures. We advocate the incorporation of vector control in the Global Programme to Eliminate Lymphatic Filariasis as it can potentially decrease the time required for eliminating lymphatic filariasis.

Study on the factors affecting the MDA programme in Kerala state

The Mass Annual Single dose DEC administration (MDA) was initiated in India from 1997. In Kerala MDA was studied as a pilot project in Alappuzha and Kozhikode District from 2000-04 and the first round of MDA was launched in Kerala covering eleven endemic districts, in March 2005. On evaluation, the drug distribution coverage, compliance, etc. were found to be not satisfactory and a need to elicit the factors for poor performance of MDA is felt essential. The main reasons for poor performance of MDA in Kerala state were the lack of adequate prior information to the target population regarding the importance LF elimination programme and inadequate awareness. The fear of side reactions, antipropagonda, poor IEC activities repeated postponement of programme, insufficient time for mobilisation etc. were the other reasons for poor compliance. The purpose of the present study was to bring the observations to the notice of the authorities so that appropriate remedial measures are incorporated.

Expression of matrix metalloproteinases (MMP-1, MMP-2 and MMP-9) and their inhibitors (TIMP-1 and TIMP-2) in oral submucous fibrosis

Immunohistochemical staining of formalin fixed, paraffin embedded tissue sections of OSF for MMPs-1,2,9 and their tissue inhibitors TIMP-1and 2 was performed using monospecific antibodies coupled with gelatin zymography (MMP-2 and 9) for measuring enzymatic activity quantitatively and for distinguishing the active from the inactive variants of enzymes. The present study, contrary to earlier reports, recorded statistically significant increase in the levels of stromal expression of MMP-1, MMP-2 and MMP-9 and TIMP-1 and TIMP-2 using monospecific antibodies reacting against tissue antigens. The simultaneous increase in reactivity of MMPs and TIMPs poise difficulty in interpretingthe results of this study. The possible reasons for this result, against the backdrop of existing knowledge, were attempted in this study.

Mass drug administration against lymphatic filariasis: experiences from Kozhikode district of Kerala State

The mass DEC drug administration to eliminate lymphatic filariasis in Kozhikode district was monitored from 2001 to 2003 to assess the drug distribution coverage, compliance, reasons for non-compliance, side reactions, mf prevalence and intensity, infection and infectivity rates in the vector. The drug distribution coverage and compliance were much below the required level. "No disease so not necessary" (42.5%) and "fear of side reactions" (25.2%) were the two major reasons for non-compliance. The adverse reactions were minimal. No appreciable changes were found in the mf prevalence and intensity. For the successful implementation of the MDA programme, proper planning, intense and timely efforts to motivate the community and innovative drug delivery strategies are required.

Effect of Caralluma fimbriata extract on appetite, food intake and anthropometry in adult Indian men and women

Caralluma fimbriata is an edible cactus, used by tribal Indians to suppress hunger and enhance endurance. The effect of Caralluma extract was assessed in overweight individuals by a placebo controlled randomized trial. Fifty adult men and women (25-60 years) with a body mass index (BMI) greater than 25 kg/m2 were randomly assigned into a placebo or experimental group; the latter received 1 g of Caralluma extract per day for 60 days. All subjects were given standard advice regarding a weight reducing diet and physical activity. At the end of 30 and 60 days of intervention, blood glucose and lipids, anthropometric measurements, dietary intake and assessment of appetite was performed. Waist circumference and hunger levels over the observation period showed a significant decline in the experimental group when compared to the placebo group. While there was a trend towards a greater decrease in body weight, body mass index, hip circumference, body fat and energy intake between assessment time points in the experimental group, these were not significantly different between experimental and placebo groups. Caralluma extract appears to suppress appetite, and reduce waist circumference when compared to placebo over a 2 month period.

Impact of single dose of diethylcarbamazine and other antifilarial drug combinations on bancroftian filarial infection variables: Assessment after 2 years

The impact of single dose mass drug administration of diethylcarbamazine (DEC), DEC with albendazole (ALB), and ivermectin (IVR) with albendazole, was examined on the human bancroftian filarial infections in village scale trials in south India, from a follow-up study after 2 years. The treatment arms administered with DEC alone and DEC+ALB demonstrated long-term benefits in reducing microfilaraemia significantly (P<0.05), while antigenaemia reduction was negligible. The arm with ALB+IVR did not show such reductions. Among the antigenaemic and microfilaraemic individuals, 87% became amicrofilaraemic in DEC+ALB arm, which were higher than that observed in the other 2 treatment arms. Among amicrofilaraemics (but Ag+), nearly 35% cleared of infection in DEC+ALB, while 26% and 6% in DEC alone and IVR+ALB arms, respectively. The drug combination DEC+ALB was observed to demonstrate a significant impact in reducing filarial infection even after 2 years post treatment.

Community-based study to assess the efficacy of DEC plus ALB against DEC alone on bancroftian filarial infection in endemic areas in Tamil Nadu, south India

As part of the Global Programme for Elimination of Lymphatic Filariasis (GPELF), India is implementing mass drug administration (MDA) with annual single dose of diethylcarbamazine (DEC) with and without albendazole (ALB). The impact of MDAs on filarial infections and soil-transmitted helminth (STH) infections was assessed during a 3-year period in two communities, one with DEC + ALB and the other with DEC alone. Prior to each MDA (during 2001, 2002 and 2003), filarial indices (microfilaraemia and antigenaemia) were assessed from blood samples of 450-650 persons aged 2-25 years and STH infections in stool samples (Kato-Katz method) from 325 to 500 children aged 9-10 years. Mosquitoes resting indoors were collected to determine the filarial infection status. The microfilaraemia prevalence decreased significantly (P < 0.05) in both arms, with the highest decline in the DEC + ALB arm (72%vs. 51%). Decline in micrefilaria intensity was also higher in the DEC + ALB arm (81.4%vs. 48.5%). In this arm alone, the antigenaemia prevalence was reduced significantly (62%; P < 0.001). The reduction in STH prevalence was lower in the DEC alone arm (6.5%; NS) than in the DEC + ALB arm (70.9%; P < 0.001). Also, the egg reduction in DEC alone arm was only half that of DEC + ALB arm (49%vs. 97%). Our community-based follow-up study showed higher and sustained benefits with regard to filarial and STH infections for the two-drug arm over the DEC alone arm. The trends suggest that at least 10 MDAs may be necessary to achieve the goal of elimination.

Undifferentiated carcinoma of the submandibular salivary gland with fulminant clinical course: a case report

Undifferentiated carcinoma of salivary glands is too poorly differentiated to be classified as any of the specific group of carcinomas. This is a rare disease, the incidence of which is rather low-to-very low in the Indian subcontinent. The tumor can assume an aggressive clinical behavior characterized by disseminated metastases. The prognosis is rated as dismal; as evidenced by this clinical report of a tumor in the submandibular salivary gland with synchronous metastases to the skull bones and in to the intracranial fossa. The putative relationship of the tumor to Epstein-Barr virus (EBV) infection is discussed.

Natural survivorship of immature stages of Culex vishnui (Diptera: Culicidae) complex, vectors of Japanese encephalitis virus, in rice fields in southern India

The development and survival of immatures of Culex vishnui (Diptera: Culicidae) complex, vectors of Japanese encephalitis virus, were studied in transplanted rice, Oryza savita L., fields during three crop growing seasons. The total duration of development from the first instar to adult emergence varied from 6 to 8 d. Survival rate estimates ranged from 0.003 to 0.524, but they generally were <0.1. Unusually high survival rates (0.192-0.524) were observed in summer and long-term monsoon crop seasons during 1993. A multiple regression method using backward elimination was used to analyze the factors responsible for these variations. The model identified nine parameters related with survival rates that explained 99% of the variance. Area of water surface and hardness were negatively related, whereas green algae, notonectid adults, anisopterans, dytiscids, salinity, water depth, and dissolved oxygen were positively associated with immature survival.

Long-term study of Japanese encephalitis virus infection in Anopheles subpictus in Cuddalore district, Tamil Nadu, South India

OBJECTIVE

To investigate the role of Anopheles subpictus Grassi as a vector of Japanese encephalitis virus (JEV) transmission in Cuddalore, an area of Tamil Nadu endemic for the disease.

METHOD

We collected 98 pools (4,900 specimens) of wild adult male An. subpictus mosquitoes outdoors during dusk hours and screened them for JEV antigen by antigen-capture Enzyme Linked Immunosorbent Assay. Additionally, over a period of 1 year, we tested 166 pools (8,300 specimens) of wild adult female An. subpictus mosquitoes collected indoors for JEV.

RESULTS

Four pools of male An. subpictus tested positive. This indicates possible natural transovarial transmission of the virus through An. subpictus. Nineteen female pools were positive with a minimum infection rate of 2.3. From January through March the maximum infection rate was highest: 5.0 compared with 1.7 between April and September and 2.1 from October to December, although the difference was not statistically significant. From the 19 positive female pools, four isolates were confirmed as JEV by insect bioassay.

CONCLUSION

The role of An. subpictus as a secondary vector in JEV transmission in Cuddalore, Tamil Nadu lends support to the hypothesis of periodic epidemics in the region.

Pentoxifylline therapy : A new adjunct in the treatment of oral submucous fibrosis

OBJECTIVE

This study was designed to determine the effect of pentoxifylline (Trental) on the clinical and pathologic course of oral submucous fibrosis. This drug is a methylxanthine derivative that has vasodilating properties and was envisaged to increase mucosal vascularity.

STUDY DESIGN

This investigation was conducted as a randomized clinical trial incorporating a control group (Standard drug group SDG, multivitamin, and local heat therapy) in comparison to pentoxifylline test cases (Experimental drug group EDG, 400mg 3 times daily, as coated, sustained release tablets). The stipulated treatment period was 7 months and a total of 29 cases of advanced fibrosis (14 test subjects and 15 age and sex matched diseased controls) were included in this study and 100% compliance was reported at the end ofthe test period.

RESULTS

Mild gastric irritation that could be managed by diet protocols was the only untoward symptom reported during this trial. Review of the patients and controls was done at an interval of 30 days and subjective and objective measurements were recorded. The follow up data at each visit with respect to each other and to base-line values was calibrated using a nonparametric test of Mann-Whitney (Kruskal-Wallis test). Significant comparisons with regard to improvement were recorded as objective criteria of mouth opening (t=11.285, p= 0.000), tongue protrusion (t= 3.898, p = 0.002), and relief from perioral fibrotic bands (p = 0.0001554). Subjective symptoms of intolerance to spices (p = 0.0063218), burning sensation of mouth (p = 0.0005797), tinnitus (p=0.000042), difficulty in swallowing (p=0.0000714). and difficulty in speech (p=0.0000020) were also recorded significant improvement at the end of the trial period.

CONCLUSION

This pilot investigation points to the effectiveness of pentoxifylline as an adjunct therapy in the routine management of oral submucous fibrosis.

Efficacy of thermal fog application of deltacide, a synergized mixture of pyrethroids, against Aedes aegypti, the vector of dengue

We evaluated the efficacy of indoor and peridomestic thermal fog applications of deltacide, a synergized mixture of pyrethroids (S-bioallethrin 0.7% w/v, deltamethrin 0.5% w/v and piperonyl butoxide 8.9% w/v) against adult populations of Aedes aegypti in Chennai, Tamil Nadu, India. We bioassayed adult caged mosquitoes, counted indoor resting and human landing adult mosquitoes and assessed the percentage of potential breeding sites with Aedes larvae. The bioassay mortalities indicated that the knockdown and killing effect was greater when fogging was applied inside houses rather than around them. Peridomestic thermal fogging reduced the resting and biting populations by 76% and 40%, respectively for the 3 days after treatment, whereas indoor fogging suppressed adult populations for 5 days.

Decline of brugian filariasis in Cherthala taluk, Alappuzha district, Kerala

A total of 4492 persons from 5 panchayats and 1 town were investigated from the Brugia malayi most endemic taluk of Cherthala, Alappuzha district of Kerala state. The urban area in Cherthala taluk only revealed mf carriers; mf rate was 0.13%. Rural areas in Cherthala taluk were free from infection. Microfilaria rate had declined by 99.5% and disease rate by 90.7% in Cherthala compared to 1934 prevalence. Shedding of sheath by B. malayi microfilariae was recorded for the first time in India. The youngest person with microfilaria and disease manifestation was 4 1/2 and 9 years respectively. All the 3 major vectors, Mansonia annulifera, Ma.uniformis and Culex quinquefasciatus were prevalent throughout. Complete disappearance of brugian filariasis from this taluk is a distinct possibility. The reasons for the drastic decline are discussed.

Characterisation and quantification of mucosal vasculature in oral submucous fibrosis

AIM

Quantitative assessment of the mucosal vascularity in oral sub mucous fibrosis (OSF) by image analysis using OPTIMAS ver 6.0 software. The vascularity was assessed by estimating (a) the mean vascular density, (b) the mean vascular area percentage, and (c) the mean vascular luminal diameter.

SUBJECT AND METHODS

Twenty (20) OSF and ten (10) age and sex matched healthy volunteers comprised the study group. The 5 microm thick H and E stained mucosal sections were examined and quantified in an image analyzer for number, size, density of vessels, and percentage of vascular area using an area morphometry tool. ANOVA is used to test equality of several means without affecting Type 1 error.

RESULT

The mean vascular density is found to be more or less same in the test and control samples (F = 0.82, P>0.05). The mean vascular percentage area shows an increasing trend as the disease progresses (F = 8.63, p<0.01). The mean vascular luminal diameter also shows an increasing trend as the disease progresses (F = 34.1, p<0.001).

CONCLUSION

The usual tissue reaction resultant to ischaemia / hypoxia does not seem to operate in this disease, which is preconditioned by significant stromal changes as part of the disease process. The mean vascular dilatation noted is assumed to be an adaptive response to compensate tissue ischaemia/hypoxia.

Short report: observations on the multiple feeding behavior of Culex tritaeniorhynchus (Diptera: culicidae), the vector of Japanese encephalitis in Kerala in southern India

A study was undertaken in villages endemic for Japanese encephalitis (JE) in Kerala in southern India during the period 1998-2001 to determine the host-feeding pattern of Culex tritaeniorhynchus, the major vector of JE in southeast Asia. A total of 3,067 blood-engorged Cx. tritaeniorhynchus were tested and 2,553 (82.2%) of the samples could be identified. Culex tritaeniorhynchus had fed mainly (56.6%) on cattle. Pig feeding accounted 6.3% of the total samples. Some samples (n = 980, 38.3%) were of serologic mixed origin. Of 980 mixed blood-fed mosquitoes, 975 (99.5%) had imbibed blood from two distinct hosts and 5 (0.5%) imbibed blood from three distinct hosts. Mixed blood meals were mostly (96.7%) from cattle and goats. The epidemiologic implications of multiple feeding of Cx. tritaeniorhynchus on dampening (dead-end) hosts such as cattle and goats in the transmission of JE virus is discussed.

Japanese encephalitis virus (JEV) is an important cause of encephalitis among children in Cuddalore district, Tamil Nadu, India

BACKGROUND

Japanese encephalitis (JE) is endemic in Cuddalore district, Tamil Nadu (TN), Southern India. The reports of JE cases from the local hospitals did not reflect the actual disease burden. It is likely that these cases were attending the nearby referral hospitals, for want of better treatment facilities.

OBJECTIVES

Between July 2002 and February 2003, a pilot study was undertaken to examine whether JE was a component of paediatric acute encephalitis syndrome (AES) reported to two major referral hospitals adjacent to Cuddalore, and to map the distribution of the JE cases.

STUDY DESIGN

A total of 58 hospitalized children [0-15 years] with AES were investigated. Other than the routine laboratory investigations, either CSF or sera or both [depending on the availability] collected from these children were analyzed at Center for Research in Medical Entomology, Madurai (TN) for JEV-antigen, antibody detection, virus isolation and virus genome detection by indirect immunofluorescence, MAC enzyme linked immunosorbent assay (ELISA), insect bioassay and by reverse transcriptase polymerase chain reaction (RT-PCR), respectively.

RESULTS

JE was established in 17 (29%) of 58 AES cases; half of the AES cases [31/58, 53%] and 59% [10/17] of JE cases were confined to JE-endemic areas in Cuddalore district. The JE confirmation scored by different assays varied according to the clinical phase of the illness. The attack rate was high among the children aged 3-8 years. The monthly distribution of acute encephalitic syndrome cases followed the distribution of JE cases [coinciding with the rainy season in this region] suggesting encephalitis of JE origin.

CONCLUSION

In JE-endemic areas, the actual JE burden can be estimated by the collection of JE case reports from the local hospitals and from the referral hospitals. Building of diagnostic facilities in hospitals for JE is necessary to achieve this goal.

Familial occurrence of oral submucous fibrosis: report of eight families from northern Kerala, south India

BACKGROUND

Oral submucous fibrosis (OSF) is an archetype of pathological fibrosis due to possibly its presence for centuries amongst people of Indian ethnic extraction. The WHO criteria for a precancerous condition accords well with this disease. The fact that the disease has been reported in at least few subjects who do not practice the habit of areca nut chewing and the inability to prove a dose-effect relationship in almost all cases, the question arose whether there is a predisposition for the disease.

METHODS

A house- to-house survey was carried out in northern Kerala, South India, for the detection of early and advanced OSF from June 2003 through May 2004. An analysis of the family pedigrees of all patients with a positive history of fibrosis has been carried out.

RESULTS

Preliminary analysis of the family survey revealed that OSF tends to aggregate in families. The pedigrees of eight (8) such families presented here and the concept of OSF having a genetic predisposition to its occurrence revisited.

CONCLUSION

The view that OSF having a family predilection, at least in a proportion of cases, and its tendency for familial linkage seems to be apparent by this study. This rather denovo observation of a trend relationship between OSF risk and the number of putative high-risk genotypes should be separately evaluated for the collagen metabolizing and cross-linking pathways. Establishing familial linkage of the disease seems to be an initial step in deciphering further the molecular pathways involved in its causation and biologic progression.

Effectiveness of two annual, single-dose mass drug administrations of diethylcarbamazine alone or in combination with albendazole on soil-transmitted helminthiasis in filariasis elimination programme

A longitudinal community-trial on the control of soil-transmitted helminths (STHs), as part of a lymphatic filariasis elimination campaign, was taken up in two revenue blocks of southern India in the years 2001 and 2002 to assess the impact of two annual single-dose mass drug administration (MDA) of diethylcarbamazine (DEC) + albendazole (ALB) with that of DEC alone. The prevalences and intensities of STHs were studied among cross-sectional samples of school children aged 9-10 years by using the Kato-Katz technique at baseline and 11 months after each MDA. The combined drug mass treatment produced a higher reduction in the prevalence (RIP) (51-77%) and the egg reduction rate (ERR) (92-98%) compared with 12-15% RIP and 58-62% ERR of DEC alone mass treatment. The effect of two-drug therapy after two annual treatments was relatively long lasting as shown by RIP and ERR indicating that the reinfection rates were relatively lower in this approach than single-drug therapy. This study demonstrates that mass drug co-administration of DEC + ALB in Global Programme for Elimination of Lymphatic Filariasis (GPELF) targeted at the community had a synergistic and sustainable effect against soil-transmitted helminthiasis and provided considerable 'beyond filariasis' benefits. The additional advantages accrued to the community underscore the importance of scaling-up GPELF to cover the entire population at risk.

Hospital- and laboratory-based investigations of hospitalized children with central nervous system-related symptoms to assess Japanese encephalitis virus etiology in Cuddalore District, Tamil Nadu, India

A collaborative investigation of hospitalized encephalitic children in south India, between July 2002 and February 2003, has indicated that Japanese encephalitis was confirmed in 27.3% of these children. In developing countries, assessment of actual Japanese encephalitis disease burden requires strengthening of diagnostic laboratory capacities at hospitals.

Japanese encephalitis in India: an overview

Japanese encephalitis (JE)-epidemics have been reported in many parts of the country. The incidence has been reported to be high among pediatric group with high mortality. The incidence of JE in recent times is showing an increasing trend. It appears that JE may become one of the major public health problems in India, considering the quantum of the vulnerable pediatric population, the proportion of JEV infections among the encephalitic children and wide scattering of JE-prone areas. JE burden can be estimated satisfactorily to some extend by strengthening diagnostic facilities for JE confirmation in hospitals and by maintenance of contact with the nearby referral hospitals to collect the particulars on JE cases. Vaccination proves to be the best to protect the individual against any disease. In the case of JE, it is essential to immunize the pigs (amplifying host) also to interrupt the transmission of the disease.

Impact of two annual single-dose mass drug administrations with diethylcarbamazine alone or in combination with albendazole on Wuchereria bancrofti microfilaraemia and antigenaemia in South India

A two-arm community-based lymphatic filariasis elimination trial is being carried out in Tamil Nadu state, India to assess the effect of 2 annual single-dose mass drug administrations of diethylcarbamazine + albendazole (DEC + ALB) on microfilaraemia and antigenaemia in one arm, and diethylcarbamazine(DEC) alone in the other arm. In a cross-sectional survey at each time-point, 450-650 subjects in childhood (2-9 years old) and young adulthood (10-25 years old) were screened from each treatment arm. After 2 annual mass drug administrations, microfilaraemia prevalence in the 2-drug arm was reduced by 54% and 62% in the 2-9 year old and 10-25 year old groups respectively; and corresponding figures for the single-drug arm were 26% and 37%. Though higher reductions were recorded for geometric mean intensity of microfilaraemia in the 2-9 year old groups for both treatment arms, reduction was more pronounced in the 2-drug arm than the single drug arm (74% vs. 24%) in the 10-25 year old group. The reduction in the antigenaemia prevalence in the 2-9 year old group was evident in both treatment arms, but in the 10-25 year old group the reduction was only 16.8% in the 2-drug arm. Our results suggest that the annual, single-dose combination (DEC + ALB) mass treatment regimen has an enhanced effect against bancroftian filariasis compared to single-drug therapy.

Cell death does not herald epithelial involution ("atrophy") in oral sub mucous fibrosis: a TEM study

The disease progression in oral submucous fibrosis (OSF) seems to be in a biphasic manner, along both fibroblastic and keratinocytic lineages. The epithelial malignancy is considered to be a sequel of connective tissue changes. "Atrophy" of epithelium makes it amenable to the effect of oral carcinogens. This concept looks rather simplistic in the light of the current understanding of epithelial cell biology. So the concept of epithelial "atrophy" needs redressal against the backdrop of recent investigations. 12 cases of clinically and histologically advanced OSF cases (M:F = 4:8) who were habitual areca-quid chewers comprise the study group. 5 (M:F=1:4) non-OSF, non-areca-nut chewing healthy volunteers, constituted the control group. Biopsy was done and the sections were processed for light and electron microscopy. Cell countings were made based on established criteria for apoptosis and necrosis under the high resolution of a TEM and electron micrographs were taken. The Apoptotic Index (A1) calculated for the diseased mucosa was 3.0 +/- 1.3 and for the control was 2.1 +/- 1.5 (X2 = 1.21, df= 1, p>0.05). The necrotic indices (NI) were respectively, 2.5 +/- 0.6 and 2.0 +/- 1.3 (X2 = 0.24, df = 1, p>0.05). The Absolute Cell death Index (ACI), which is the cumulative figure of apoptosis and necrosis indices, was 5.5 and 4.2 respectively for diseased and normal samples (X2 = 1.8, df = 1, p>0.05). The inability to compute an increased ACI in OSF epithelium, when compared to normal, goes against the concept of epithelial "atrophy". Atrophy envisages an increased apoptotic cell death of keratinocytes, induced by the same signals that caused atrophy and this may contribute to loss of cell of an entire organ. This basic concept in pathology seems to be unfounded with disease. This prompted us for an alternative concept in favour of a reduced proliferation index of the adult stem cell compartment of the oral epithelium. So this study favours the concept of epithelial hypoplasia, rather than atrophy, which causes thinning of surface epithelium in advanced OSF.

Morphohistometric analysis of advancing tumor fronts in malignancies associated with oral submucous fibrosis

The objective of this study was to address retrospectively the invasive tumor fronts of epithelial neoplasms associated with OSF and non-associated tumors. Review of a data base of 25 OSF patients who have had concurrent oral squamous cell carcinoma served as the test sample. The controls constituted an equal number of age standardized (roughly) squamous cell carcinomas, non-associated with OSF. The diagnsis and grading were performed based on established criteria. Altogether a total of 8 histopathological variables were evaluated related to the advancing tumor fronts. After selection of cut-off levels, single parameter analysis by means of univariate test revealed significant result in none. A Total Malignancy Score (TMS) of 14.98 and 15.13(mean) were recorded for test and control respectively. Multivariate analysis showed that degree of nuclear plemorphism (p=0.015) and the pattern of invasion (p=0.003) were the only two variables which significantly affected the TMS. OSF associated tumors did not show features unique to it and therefore its response to therapy need not vary significantly from conventional cases.

The role of urea in the oviposition behaviour of Japanese encephalitis vectors in rice fields of South India

The effect of urea on the oviposition behaviour of culicine vectors of Japanese encephalitis was studied in rice fields. Gravid females had a strong preference for oviposition in urea treated areas in rice fields, while no such preference was exhibited in untreated areas. The egg laying declined in the area where urea treated water surface had a mechanical barrier, which allowed volatile fractions to escape, but prevented contact with the water. Urea was shown to act as an oviposition attractant/stimulant for Culex tritaeniorhynchus, but its role was not clear for Cx. vishnui, as the number of egg rafts obtained for the latter species was low.

Transmission intensity index to monitor filariasis infection pressure in vectors for the evaluation of filariasis elimination programmes

We conducted longitudinal studies on filariasis control in Villupuram district of Tamil Nadu, south India, between 1995 and 2000. Overall, 23 entomological (yearly) data sets were available from seven villages, on indoor resting collections [per man hour (PMH) density and transmission intensity index (TII)] and landing collections on human volunteers [PMH and annual transmission potential (ATP)]. All four indices decreased or increased hand-in-hand with interventions or withdrawal of inputs and remained at high levels without interventions under varied circumstances of experimental design. The correlation coefficients between parameters [PMH: resting vs. landing (r = 0.77); and TII vs. ATP (r = 0.81)] were highly significant (P < 0.001). The former indices from resting collections stand a chance of replacing the latter from landing collections in the evaluation of global filariasis elimination efforts. The TII would appear to serve the purpose of a parameter that can measure infection pressure per unit time in the immediate household surroundings of human beings and can reflect the success or otherwise of control/elimination efforts along with human infection parameters. Moreover, it will not pose any additional risk of new infection(s) and avoids infringement of human rights concerns by the experimental procedures of investigators, unlike ATP that poses such a risk to volunteers.

Dengue disease spectrum among infants in the 2001 dengue epidemic in Chennai, Tamil Nadu, India

An investigation in a referral pediatric hospital has indicated that during a recent dengue outbreak in Chennai, Tamil Nadu, India, dengue in infancy constituted 20% of total dengue virus infections with low mortality rates in this hospital. In developing countries, strengthening of dengue management capabilities at hospitals can prevent dengue-related deaths in infants.

Sustainability of soil-transmitted helminth control following a single-dose co-administration of albendazole and diethylcarbamazine

We evaluated the long-term impact of single-dose diethylcarbamazine plus albendazole combination therapy with that of diethylcarbamazine alone on the control of soil-transmitted helminths (STH) in 2 blocks (revenue units) of Villupuram district, south India, as part of an ongoing mass drug administration (MDA) campaign for the elimination of lymphatic filariasis in 2001. The prevalence and intensities of STHs were studied in 287 children, aged 9 and 10 years (136 in the combination therapy cohort and 151 in the diethylcarbamazine alone cohort), using the Kato-Katz technique to examine stool samples at 4 time-points (baseline, and 3 weeks, 6 months and 11 months after MDA). The combination therapy showed long-term efficacy against STHs and the magnitude of control remained at a moderate and significant level for 11 months after MDA compared with the moderate gains of diethylcarbamazine alone. Single-dose MDA with albendazole and diethylcarbamazine combination therapy may prove to be a good strategy in treating multiple parasitic infections in endemic communities.

Long-term population migration: an important aspect to be considered during mass drug administration for elimination of lymphatic filariasis

Annual 2-drug, single-dose mass drug administration (MDA) to 80-90% of the eligible population for 4-6 years are pre-requisites for the successful elimination of lymphatic filariasis (LF) from endemic communities by interruption of transmission and eventual elimination of new infections. In an experimental intervention project on the control of LF in Villupuram district of Tamil Nadu state, India, migration patterns of the villagers were investigated to determine the appropriate timing to implement MDA in order to attain high coverage in a village-level study. Between January and December 1997, 16 observations took place at 3-week intervals, following MDA with two drugs viz., diethylcarbamazine and ivermectin, in July-August 1996. The migrants from the village constituted 17-27% at different points of time and both short-term and long-term migrating patterns were observed. More villagers were available during the agricultural season (September-January), peaking around mid-January [83%; significantly higher (P < 0.05)] than during most of the remaining months, including a substantial portion of the migrant population. There is an urgent need to reschedule the yearly MDA in this area to take place in January and to plan mopping up operations by involving local self-help groups to include migrants (both short-term and long-term) in the LF elimination efforts.

Longitudinal studies in South Indian villages on Japanese encephalitis virus infection in mosquitoes and seroconversion in goats

Japanese encephalitis (JE) is endemic in Cuddalore district, Tamil Nadu, where Culex tritaeniorhynchus Giles was the major vector. We screened 45 100 adult female Cx. tritaeniorhynchus (902 pools) by enzyme-linked immunosorbent assay and isolated and confirmed JE virus (JEV) by using an insect bioassay system. We had 69 isolates of which 62 (90%) were identified as JEV. The average vector abundance per man hour for Cx. tritaeniorhynchus was 324.5 per month for the period June 1998-May 2000. The average minimum infection rate (MIR) per month in Cx. tritaeniorhynchus was 1.4 (range 0.0-5.6). Every year, a new batch of goats, 20 in the first year and 31 in the second year, born during the non-JE transmission period (January-June), aged <6 months and negative for haemagglutination inhibition (HI) antibodies were procured and placed in the villages as sentinels. Fortnightly, blood specimens were collected from these goats and tested for JE antibodies by HI test. Seroconversions (SCs) were recorded in 14 goats (70%) in the first year and 23 goats (74%) in the second year. JE HI antibody titres in goats were low (1:10-1:80) and these levels declined to undetectable levels in about 4 weeks following SCs. The time sequence of events indicated that four of five peaks of MIR in mosquitoes were followed 1-3 months later by peaks in the proportion of seroconverted goats. We suggest the screening of goats and cattle as a more feasible tool to stratify areas according to JE infection risk to the human population through the regular health system rather than screening mosquitoes using monoclonal antibodies, which is possible only in specialized laboratories.

Liver ultrasound and faecal copper estimation in oral submucous fibrosis

There is no evidence of an increased quantity of ingestion of copper in areca nut chewers by way of habitually swallowing the 'quid juice' allegedly contain 'appreciable quantity' of soluble copper. Our experimental findings are favour of assuming that the amount of copper ingested, if at all, is well within the threshold limit of tolerance and therefore of no clinical significance. In conjunction with our earlier observation this study again proved the absence of visible and clinically/diagnostically detectable fibrosis in visceral organs, that includes liver, in patients suffering from advanced oral submucous fibrosis.

Cost-effectiveness of the use of vector control and mass drug administration, separately or in combination, against lymphatic filariasis

The costs and effects of two intervention strategies for the control of bancroftian filariasis-annual mass drug administrations (MDA) with a combination of diethylcarbamazine and ivermectin, with or without integrated vector control (VC)-were estimated in rural villages in South India. The aim was to compare the cost-effectiveness of MDA alone with that of MDA plus VC. Control of the local vector, Culex quinquefasciatus, was based on the application of polystyrene beads to cesspits, the treatment of drains with larvicidal Bacillus sphaericus and the stocking of wells with larvivorous fish. An itemized cost menu was used to cost MDA and MDA + VC, retrospectively. The annual transmission potential was used to assess the direct outcome of the disease-control methods, whereas the prevalence and intensity of microfilaraemia were used as indicators of the impact of each method. The per-capita costs were 1.49 U.S. dollars for two rounds of MDA, 1.70 U.S. dollars for 2 years of VC and, therefore, 3.19 U.S. dollars for 2 years of MDA + VC. Integration of VC with MDA did not appear to be cost-effective: it cost an estimated 1.80 U.S. dollars to stop an infective mosquito biting a villager using MDA alone but 3.32 U.S. dollars to achieve the same result using MDA + VC. Similarly, the cost to reduce the prevalence of microfilaraemia in a three-village group by 1% was only 96.62 U.S. dollars for MDA alone but 201.16 U.S. dollars when vector control was integrated. The implications of these results for the control and elimination of filariasis in Indian village communities, and the options for sharing and minimizing costs, are discussed.

Age of treatment of undescended testis--a study

A retrospective study was conducted for a period of 4 years during 1992-1995 at Medical College Hospital, Alappuzha, Kerala to find out whether boys with undescended testis got treated at ideal age. Discharge summaries of boys who were treated for undescended testis in this hospital were studied. There were 139 patients with 162 undescended testes. Mean age of operation was 5 years (range--11 months to 12 years). There were 19.4% patients who were less than 2 years of age. It was found out that 11.1% of total testes were atrophic/vanished. Orchiopexy was done in almost all remaining cases. Majority of boys with undescended testis attended for treatment at a higher age than that recommended. The ideal age of treatment at present and its scientific basis are highlighted.

The influence of the mass administration of diethylcarbamazine, alone or with albendazole, on the prevalence of filarial antigenaemia

The current Indian campaign for the elimination of lymphatic filariasis is largely based on mass drug administration (MDA). As part of this campaign, villagers in the Tirukoilur and Mugaiyur 'blocks' (i.e. revenue units) of Villupuram district, in Tamil Nadu, India, were treated with diethylcarbamazine (DEC), either alone (Mugaiyur) or with albendazole (Tirukoilur), in March 2001. The efficacy of treatment, in each of the two treatment arms, was evaluated by determining the percentages of the subjects who were carrying antigen from adult Wuchereria bancrofti before, 6 months and 12 months after the MDA. In a cross-sectional survey at each time-point, commercial, immunochromatographic tests were used to check 1000-1200, randomly selected, young residents (aged 2-25 years) of 18 index villages for the antigen; at least 300 villagers aged 2-9 years and at least 170 aged 10-25 years from each treatment arm were screened in each survey. Before the MDA, 12.7% of the subjects aged 2-9 years and 23.6% of those aged 10-25 years were found to be positive for the filarial antigen. Although only about 50% of villagers aged 2-9 years were successfully treated, MDA (with DEC alone or DEC plus albendazole) led to a significant (28.7%) reduction in the prevalence of antigenaemia in this age-group 6 months later (P<0.05). Although, the prevalences of antigenaemia among those aged 2-9 years were higher 12 months post-treatment than 6 months post-treatment, they were still lower (by 16%-23%) than those observed pre-treatment. The addition of albendazole to the DEC treatment appeared to offer no additional benefit in terms of the prevalence of antigenaemia in children aged <10 years; in fact, the use of DEC alone produced a slightly greater reduction in the prevalence of antigenaemia than the use of both DEC and albendazole. In the block given MDA based on both DEC and albendazole, the prevalences of antigenaemia among the villagers aged 10-25 years were 19.4% and 16.6% lower 6 and 12 months post-treatment, respectively, than observed pre-treatment. Curiously, in the block given DEC alone, the prevalences in this age-group were higher at both post-treatment follow-ups (by 17.4% at 6 months and 35.1% at 12 months) than observed pre-treatment. In concurrent experimental studies, high drug compliance (90%) among young children (aged 2-5 years) led to a pronounced (62.6%) reduction in the prevalence of antigenaemia after one MDA. In follow-up studies of those found antigen-positive, 40% of those aged 2-9 years but only 23% of those aged 10-25 years cleared their antigenaemias after three (annual) MDA. To maximize the benefits of MDA, greater efforts should be made to increase treatment coverage among young children.

Efficacy of co-administration of albendazole and diethylcarbamazine against geohelminthiases: a study from South India

The efficacy of single-dose combination drug therapy with diethylcarbamazine (DEC) plus albendazole (ALB), and single-drug therapy with DEC alone against geohelminths was compared as part of a mass drug administration (MDA) for elimination of filariasis. This study was conducted in two blocks of Villupuram District of Tamil Nadu State, India, covering a population of 321 000 including about 100 000 children 1-15 years of age. Prevalence and intensity of geohelminth infection were determined by the Kato-Katz technique immediately before and 3 weeks after the MDA. A pre-treatment cross-sectional survey was undertaken in 18 statistically selected villages out of 204 villages, including 646 school children. About 60% were infected with one or more geohelminths. The overall prevalence rates were 53.9%, 12.4% and 5.7% for Ascaris lumbricoides, hookworms and Trichuris trichiura, respectively. Combination therapy (DEC + ALB) produced a cure rate of 74.3% and an egg reduction rate of 97.3% for geohelminths, which were higher than the corresponding rates (30.4% and 79.0%) observed in the single drug therapy arm with DEC alone. The odds of cure with combination therapy were significantly higher for roundworm (5.3 times) and hookworms (3.5 times), then odds of cure with DEC alone. Both therapies were equally effective against trichuriasis, recording cure rates >77% and egg reduction rates >83%. In combination therapy, 53.5% of the children noticed expulsion of worms after MDA, while in single drug therapy only 20.9% did. Our study indicated that MDA of combination therapy was operationally feasible at the community level, and it may secure higher community compliance because of its perceived benefits and enhanced efficacy against geohelminths than single-drug therapy.

Further on the causation of oral submucous fibrosis

Oral submucous fibrosis is perhaps a disease of multifactorial aetiology, of which areca nut usage is definitely a causative factor. We disagree with the previous reports in that the action of areca quid on the oral mucosa is not that simplistic and is not dictated solely by the duration of exposure to it or by simple process of passive diffusion. We noted that the role of copper cannot be segregated from that of zinc, the biochemical relatedness of these two elements is well elucidated. The transport of copper in to the oral epithelium may be dictated more by the composition of the quid rather than the time of exposure. Zinc is implicated in the modulation of mucosal metallothionein, thereby interfering with copper absorption. The bioavailability of zinc in its turn depends on elements like calcium and iron present in oral fluid. The usage of slaked lime(calcium hydroxide) as as ingredient of betel quid, thereby causing an interference with zinc bioavailability is a matter of concern. Of practical importance is the processing of raw areca nut and the various proprietary forms (sachets) available in the market, the toxic effects of which varies depending on its contents. Studies on the role of geochemical factors in modulating the chemical composition of the various nut forms, thereby altering its toxic effects will be an interesting pursuit.

Resurgence in filarial transmission after withdrawal of mass drug administration and the relationship between antigenaemia and microfilaraemia--a longitudinal study

Seven village units endemic for filariasis were assigned randomly into three arms with different intervention strategies in the years 1995 and 1996. Villages in Group A received two annual mass drug administrations (MDAs) of diethylcarbamazine (DEC) plus ivermectin (IVR). Group B received the same MDAs in combination with vector control; in Group C only placebo was administered. Post-treatment evaluation in 1997 revealed marked reductions in microfilaraemia prevalences (MFP) and geometric mean intensities (GMI). Subsequently, vector control in Group B was continued by the community. Groups A and B received no MDAs between 1997 and 1999 and were re-evaluated in 1999. During this evaluation, antigenaemia prevalence (AGP) was estimated along with MFP, using immunochromatographic test (ICT) kits. The gains of the MDAs were sustained in Group B, while resurgences occurred in Group A, where annual transmission potential (ATP) rose from 21 to 631.6 and MFP doubled. Group C continued to have high ATPs (1057-1617), while Group B had very low ATPs (0-63). After Mulla's corrections, the reductions in MFP were 62.7 and 83.5% and for GMI 72.1 and 91.4% in Group A and B, respectively, compared with Group C. Vector control preserved the gains of MDAs and accounted for 55.8% and 67.1% reductions in MFP and GMI in Group B compared with Group A. The reductions in AGP were 29.4% in Group A and 39.2% in Group B against Group C. The differences between MFP and AGP were nearly uniform across all villages and there was a significant correlation (r=0.98) between the two variables. A similar significant relationship was observed between MFP and AGP values across age groups (r=0.95). Prediction of AGP values from MFP values was proposed with regression equations. We conclude that vector control would be useful as an adjuvant to chemotherapy to prevent resurgences.