Validity of Weech's formulae in detecting undernutrition in children

Primary care physicians in developing countries frequently use Weech's formulae to estimate the expected weight and height of children using age as a variable. The present study was undertaken to assess the validity of Weech's formulae in diagnosing undernutrition. We collected anthropometric information from 294 consecutive children, aged 12-59 months, who visited a health centre. Age was calculated from birth records and was recorded in completed months as well as completed years. Weight and height/length were measured using standard methods. Weight-for-age and height-for-age Z scores were calculated using WHO Anthro. Weech's formulae were used to calculate weight-for-age (%) and height-for-age (%). A cut off of < or =80.0% weight-forage and < or = 95.0% height-for-age were used to evaluate the validity of underweight and stunting respectively; a cut off of < or = 60.0% weight-for-age and <85.0% height-for-age were used for severe underweight and severe stunting respectively. Weech's formulae were found to be 100% sensitive in detecting underweight (weight-for-age Z score<-2) and stunting (height-for-age Z score<-2). When evaluating severe underweight (weight-for-age Z scorc<-3) and severe stunting (height-for-age Z scorc<-3), Weech's formulae were found to be 100% specific but the sensitivity was very low, 25.0% and 15.4% respectively. Based on the findings of our study Weech's formulae appear to be a sensitive tool to detect underweight and stunting in children between 12-59 months of age. Such formulae should however be used with caution when evaluating severe forms of undernutrition.

HCV-genotypes: a review on their origin, global status, assay system, pathogenecity and response to treatment

The present report is a review article on various aspects of Hepatitis C virus (HCV) genotypes and their subtypes. HCV has six genotypes and several subtypes showing important epidemiological and clinical implications. The information based on previous studies and presented through this article highlight the origin, classification and causes of genetic diversity, global status, detection assays, pathogenicity and response to treatment of HCV-genotypes. The six genotypes differ in 30-35% of nucleotide sites over the complete genome. The difference in genomic composition of sub-types of genotype is usually found to be 20-25%. The variability remains more frequent in structural genes as compared to non-structural or untranslated genes. Both genotypes and their sub-types show a varied prevalence globally and raise several issues related to their transmission and treatment of HCV-infection. All this information has a great significance while planning future strategies for eradication and therapeutic management of HCV. In addition, these reports produce a further scope for more studies to unravel the mystery behind HCV-genotypes and formulate guidelines to resolve this public health problem noted worldwide.

Global developmental delay and its determinants among urban infants and toddlers: a cross sectional study

OBJECTIVE

To estimate the prevalence of global developmental delay among children under 3 years of age and study the determinant factors.

METHODS

Cross sectional descriptive study was conducted in field practice areas of the Department of Community Medicine, JN Medical College, Aligarh, India. A total of 468 (243 boys and 225 girls) children aged 0-3 years were included. Developmental screening was performed for each child. A multitude of biological and environmental factors were analysed.

RESULTS

As many as 7.1% of the children screened positive for global developmental delay. Maximum delay was observed in the 0-12 months age group (7.0%). Undernutrition and prematurity were the two most prevalent etiological diagnoses (21% each). Stunting and maternal illiteracy were the microenvironmental predictors on stepwise binary logistic regression while prematurity and a history of seizures emerged significant biological predictors.

CONCLUSIONS

Developmental delay can be predicted by specific biological and environmental factors which would help in initiating appropriate interventions.

Cervical Rib causing Thrombosis of Subclavian Atery

We describe here an unusual case of thrombosis of left subclavian artery in a patient with cervical rib. The patient presented with features of ischaemia of left upper limb. X-ray chest revealed bilateral cervical ribs, longer on the left side. Color Doppler studies showed echogenic thrombus within the left subclavian artery. Angiography revealed complete occlusion of left subclavian artery. Embolectomy was done. She was planned for excision of rib. KEYWORDS:  cervical rib, thrombosis of subclavian artery.

Cervical rib causing thrombosis of subclavian artery

We describe here an unusual case of thrombosis of left subclavian artery in a patient with cervical rib. The patient presented with features of ischaemia of left upper limb. X-ray chest revealed bilateral cervical ribs, longer on the left side. Color Doppler studies showed echogenic thrombus within the left subclavian artery. Angiography revealed complete occlusion of left subclavian artery. Embolectomy was done. She was planned for excision of rib.

Cancer Diagnosis by Discrimination between Normal and Malignant Human Blood Samples Using Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy

FTIR spectroscopy is a common technique for cancer diagnosis. Applied tissue samples are heterogeneous and may be damaged in preparation procedures. Easier sampling, more available samples and also easier process with assured results would be interesting. Whole blood samples include all of these qualifications and our hypothesis was the bio-molecular changes in blood which manifest themselves in different optical signatures, detectable by FTIR spectroscopy. Noncancerous blood samples were differentiated from cancerous ones using ATR-FTIR spectroscopy and LDA classification method. Procedure was 100 percent and 90 percent accurate in prediction of cancerous or noncancerous situation for 33 known and 10 unknown samples, respectively.

Impact of etofenprox (Vectron 20 WP) indoor residual spray on malaria transmission

BACKGROUND & OBJECTIVE

A longitudinal study was carried out to assess the impact of indoor residual spray with Vectron 20 WP (etofenprox) against Anopheles culicifacies and on malaria transmission in a selected village of Dadri primary health centre (PHC), District Gautam Budh Nagar, Uttar Pradesh, India.

METHODS

Two villages, namely Patadi and Anandpur in District Gautam Budh Nagar, Uttar Pradesh, with similar malaria incidence and vector prevalence were selected for the present evaluation. In one village two rounds of indoor spraying of etofenprox (0.1 g/m(2)) were done at an interval of 12 wk and the other village was kept as control where no intervention except intensive active surveillance for early detection and prompt treatment (EDPT) was undertaken during the study period. Entomological and epidemiological data were collected using standard procedures.

RESULTS

Persistence of the effectiveness of etofenprox against An. culicifacies was observed up to 12 wk. Spraying of etofenprox significantly reduced the density (P<0.001) and proportion of parous An. culicifacies mosquitoes (P<0.05) in the experimental village. There was a significant reduction in malaria cases in the experimental village during the post-spray period when compared to the control village (P<0.05). No adverse effect was reported by the spraymen and inhabitants during and after the spray.

INTERPRETATION & CONCLUSION

Indoor residual spray of etofenprox (0.1 g/m(2)) with an interval of three months in between two rounds of spray produced the desired impact in reducing the indoor resting density of vector mosquitoes and also in curtailing malaria transmission in the sprayed village when compared with the control village without spray.

Accuracy of ultrasonography in the diagnosis of acute appendicitis

AIMS AND OBJECTIVES

To assess the accuracy of ultrasonography in the diagnosis of acute appendicitis.

METHODOLOGY

A prospective randomized study was carried in the Dept. of Radiology and Imaging, Tribhuvan University, Teaching Hospital, Maharajgunj, Kathmandu, Nepal. A total of 120 patients, who were clinically diagnosed as acute appendicitis were subjected to ultrasonography of the abdomen. A detailed ultrasonography was performed and the findings were recorded. Twenty one cases had alternate diagnosis. Ninety nine cases ultimately underwent laparotomy and the retrieved appendices were sent for histopathological examination. Intra-operative, histopathological and ultrasonographic diagnoses were then statistically analyzed.

RESULTS

Ultrasonographic, intra-operative and histopathological findings were statistically insignificant (P0.05). The sensitivity, specificity, positive predictive value, negative predictive value and accuracy percentage of ultrasonography in the diagnosis of acute appendicitis was 85.7%, 100%, 100%, 6.7% and 85.9% respectively.

CONCLUSION

Ultrasonography has a high degree of accuracy in the diagnosis of acute appendicitis. However, the diagnosis should be considered with the diameter of appendix over 6 mm. Therefore acute appendicitis with diameter of appendix having less than 6 mm should be evaluated with other diagnostic parameters.

Efficacy of PermaNet 2.0 against Anopheles culicifacies and Anopheles stephensi, malaria vectors in India

Bioefficacy of PermaNet was evaluated in both the laboratory and field against Anopheles culicifacies and An. stephensi, major malaria vectors in India. Contact bioassays were carried out after repeated washings and ring net bioassays to determine the median knockdown time of mosquitoes. Three villages were selected for the field trial: in the 1st village PermaNets were distributed, in the 2nd village untreated nets were distributed, and the 3rd village was a control. Entomological data were collected using standard procedures. The PermaNet contact bioassays showed high mortality (>80%) even after 20 washes against both the vector species. The median knockdown time of An. culicifacies and An. stephensi was 392 and 480 sec when exposed to fresh PermaNets and 472 and 986 sec when exposed to PermaNets that had been washed 20 times, respectively. PermaNets showed high efficacy in reducing the person-vector contact as evidenced by reduced person-hour density in the PermaNet village. Long-term field trials are indicated to test the impact of use of PermaNets in controlling malaria.

Impact of Olyset nets on malaria transmission in India

BACKGROUND & OBJECTIVES

Efficacy of Olyset nets, long-lasting insecticidal nets were tested from August 2003 to August 2006 against Anopheles culicifacies, the vector which transmits 60% of all malaria cases in rural India.

METHODS

Three villages in District Gautam Budh Nagar (Uttar Pradesh), India were selected for the trial and Olyset nets were distributed in one village, in another village untreated nets were distributed and the third village was kept as control where nets were not used. Entomological, and epidemiological data were collected using standard methods.

RESULTS

The use of Olyset nets reduced the indoor resting density of An. culicifacies and also reduced mosquito entry into the structures where Olyset nets were used. No mosquitoes were caught landing on the Olyset nets. There was a reduction in the parity rate of An. culicifacies in the Olyset net village as compared with untreated net and no net villages. The impact of Olyset nets was observed on malaria incidence and only one case of Plasmodiumfalciparum malaria was reported in the Olyset net village but these continued to be found in the village with untreated nets and the control.

CONCLUSION

Results of the present study confirmed that Olyset nets are highly effective in reducing the indoor resting density of mosquitoes, man-vector contact and malaria incidence.

Wash resistance and bioefficacy of Olyset net--a long-lasting insecticide-treated mosquito net against malaria vectors and nontarget household pests

During recent years, long-lasting insecticide-treated nets (LLINs) have been developed to overcome the problems of low retreatment rates, washing, and erratic dose of the insecticide resulting in the dilution of efficacy of the conventional insecticide-treated mosquito nets. These nets are treated at factory level with insecticide either incorporated into or coated around fibers. Olyset net, a polyethylene net with 2% permethrin incorporated within fibers, is one type of LLIN. Therefore, these nets were evaluated for their wash resistance and bioefficacy against malaria vectors Anopheles culicifacies Giles and Anopheles fluviatilis James (Diptera: Culicidae) and other nontarget species. Cone bioassay tests produced 100% mortality in these two vector species with 3-min exposure. Results of the bioassays on washed nets showed 100% mortality in An. fluviatilis even after 20 washings, whereas in An. culicifacies 100% mortality up to 11 washings and 80% mortality up to 20 washings were observed. Cone bioassay tests also were performed on nontarget mosquito species Culex quinquefasciatus Say; house fly, Musca domestica L.; American cockroach, Periplaneta americana (L.); head louse, Pediculus humanus capitis De Geer; and bed bug, Cimex lectularius L. with 30-min exposure. Except for bed bugs, 100% mortality was observed in these nontarget species after 24-h recovery period. In bed bugs, only 25% mortality was observed. The density of An. culicifacies and An. fluviatilis was significantly reduced in houses with Olyset nets compared with those with untreated nets or no nets. Thus, it may be concluded that Olyset nets are highly effective against malaria vectors and moderately against other nontarget household insects.

Bioefficacy of Olyset nets against mosquitoes in India

Olyset nets are highly effective in killing anopheline mosquitoes within 3 min of exposure, as evidenced in cone bioassay tests. These nets also showed their efficacy on other vector mosquitoes (Aedes aegypti and Cx. quinquefasciatus) at higher exposure periods. The efficacy remained at approximately 90% even after 20 washings at an interval of 24 h against Anopheles culicifacies and Cx. quinquefasciatus. Use of the nets inside the house also resulted in drastic reduction of daytime resting density of mosquitoes because of high repellency, excitorepellency, and killing action of the nets. Pilot studies are indicated to evaluate the impact of use of Olyset nets on vector-borne diseases, particularly malaria, and its cost-effectiveness in comparison to conventional indoor residual spraying.

Diversity in pathogenicity of Steinernema carpocapsae and its symbiotic bacterium for Spodoptera spp

Pathogenicity of five isolates of Steinernema carpocapsae (GER: Germany, BUW: Becker Underwood, KOP: Koppert, CZ: Czech Republic, BEL: Belgium) were tested against the fourth instar larvae of the cotton leaf worm, Spodoptera littoralis and the beet armyworm, Spodoptera exigua (Lepidoptera: Noctuidae) at different concentrations (0, 5, 10, 25, and 50 infective juveniles/cm2) in Petri dishes (9 cm dia.) lined with filter paper. Results obtained after 48 h exposure indicated that the pathogenicity varied in time, dose of application and host species. On S. littoralis, KOP, BUW, CZ and GER were more virulent than BEL, whereas all isolates showed 100% control of S. exigua after 72 h. The LC50 values of all five isolates were lower for S. exigua than for S. littoralis. Among the isolates tested, KOP showed the lowest LC50 value in both S. exigua (3.84) and S. littoralis (4.44 infective juveniles). To further check the pathogenicity, the symbiotic bacterium of S. carpocapsae, Xenorhabdus nematophilus, was isolated from Galleria mellonella 30 h after its infection with the nematode. Ten microlitres of 50 mM phosphate buffer containing 0, 10, 100, 1000, or 10,000 cfu were injected into the haemocel of fifth instar larvae of S. exigua. Significant differences in mortality of S. exigua larvae were observed 96 h post-injection with different bacterial doses. Cell-free filtrates of X. nematophilus were isolated from a bacterial suspension; 10 microlitres of filtrates were injected into fifth instars of S. exigua. All larvae had died 72 h post-injection. To check the insecticidal capability of X. nematophilus via oral uptake, suspensions of bacteria at concentrations of 0, 1010, 109, and 108 cfu/ml were sprayed onto tomato leaves cv. Moneymaker infected with fourth instar larvae of S. exigua. None of the larvae were killed after 24 h. Finally, we tested the virulence of selected isolates of S. carpocapsae (KOP, BUW, and BEL) in the glass-house on tomato plants infested with S. exigua or S. littoralis larvae. Nematodes were sprayed at a concentration of 2.5 billion/ha. After 48 h isolate KOP caused higher mortality (99% and 85% on S. exigua and S. littoralis, respectively), than other tested isolates. S. carpocapsae isolates BUW and BEL caused 61-65% mortality on S. exigua and S. littoralis, respectively. As most of the isolates had the same origin, viz. the ALL strain, these results demonstrate differences in pathogenicity of the production.

Laboratory and field evaluation of Hilmilin against mosquitoes

Hilmilin (diflubenzuron), an insect growth regulator, was tested for efficacy against Anopheles stephensi, Anopheles culicifacies, Aedes aegypti, and Culex quinquefasciatus in the laboratory and in field conditions. Fifty percent and 90% lethal concentrations (LC50 and LC90) of Hilmilin formulations were determined by exposing early 4th-stage larvae to serial dilutions of the formulation, and data were subjected to log probit analysis. Two doses (0.004 and 0.008 g/m2) were applied in different breeding habitats of mosquitoes with the help of stirrup pumps. Percent inhibition of adult emergence was compared according to a previously described procedure. Laboratory results revealed that both 25WP (wettable powder) and 22SL (semiliquid) formulations showed more or less the same degree of efficacy against tested mosquito species (P < 0.05). Of 4 species tested, An. stephensi was more susceptible, followed by An. culicifacies, Ae. aegypti, and Cx. quinquefasciatus. One hundred percent inhibition of adult emergence was observed at a dose of 0.0125 ppm (25WP and 22SL) against all mosquitoes tested in the laboratory. Both formulations showed almost similar effect when applied in the field at doses of 0.004 and 0.008 g/m2 in their respective preferential breeding habitats. However, the effect was more pronounced at a higher concentration (0.008 g/m2) against all species of mosquitoes. Hilmilin at a dose of 0.008 g/m2 can be used to contain mosquito breeding in stone quarries, pools, cement tanks, unused wells, unused coolers, and irrigation channels.

Larvicidal and mosquito repellent activities of Pine (Pinus longifolia, family: Pinaceae) oil

BACKGROUND AND OBJECTIVES

Various plant-based products are safe and biodegradable alternatives to synthetic chemicals for use against mosquitoes. Oil of Pinus longifolia is traditionally used for protection against mosquitoes in some rural areas but there is no documented report of its use against mosquitoes. The present study was undertaken to scientifically evaluate the activity of Pine oil against mosquitoes.

METHODS

The oil was procured from the market and its contents were chemically analysed. Larvicidal activity of oil was tested in laboratory bioassays, while repellent action was studied during whole night bait collections in field by direct application on the skin and after its impregnation on mats.

RESULTS

Results showed varying degree of larvicidal activity of Pine oil against mosquitoes with LC50 values ranging between 82 and 112 ppm. The Pine oil had strong repellent action against mosquitoes as it provided 100% protection against Anopheles culicifacies for 11 h and 97% protection against Culex quinquefasciatus for nine hours respectively. Electrically heated mats prepared from Pine oil provided, 94 and 88% protection against An. culicifacies and Cx. quinquefasciatus for 10 and seven hours respectively. INTERPRETAION AND CONCLUSION: Pine oil is effective against mosquito larvae at very higher doses which are not of any practical utility. However, Pine oil showed strong repellent action against An. culicifacies (malaria vector) and Cx. quinquefasciatus (pest mosquito). Thus its use could be popularised as mosquito repellent.

Efficacy of IGR compound Starycide 480 SC (Triflumuron) against mosquito larvae in clear and polluted water

BACKGROUND AND OBJECTIVES

An environmental friendly formulation Starycide 480 SC (Triflumuron-OMS-2015 ), a new insect growth regulator with chitin synthesis inhibitor type mode of action was evaluated against mosquito larvae in laboratory and small-scale field trials carried out in and around Delhi.

METHODS

The formulation was tested in laboratory for its bio-efficacy against late III instar mosquito larvae of different species using WHO bioassay procedure. In the field formulation was sprayed at doses of 0.3, 0.5 and 1 ppm (g/m3) in the natural breeding habitats of Anopheles and Culex mosquitoes. The impact was assessed by monitoring densities of larvae by dipper and observing the reduction in larval density and inhibition of adult emergence.

RESULTS

In the laboratory, formulation was more effective against larvae of Anopheles stephensi and Aedes aegypti than Culex quinquefasciatus, but it produced 100% inhibition of adult emergence for all mosquito species at a concentration of 0.02 ppm. In the field trials, formulation did not produce 100% reduction in the density of late stage larvae even at 1 ppm (g/m3), the highest dose tested, but it resulted in 100% inhibition of pupal formation of both Anopheles and Culex spp in different types of habitats for 3-7 weeks even at a lower dose of 0.5 ppm.

INTERPRETATION AND CONCLUSION

Application of triflumuron in the natural breeding habitats in both clean and polluted water @ 0.5 ppm (g/m3) resulted in complete inhibition of adult emergence of both Anopheles and Culex spp for 3-7 weeks. This formulation may be tested in large-scale field trials for further use in the vector control programme.

Therapeutic efficacy of antimalarial drugs along the eastern Indo-Nepal border: a cross-border collaborative study

This collaborative cross-border study was performed to determine the therapeutic efficacy of antimalarial drugs used by the National Programmes for falciparum malaria along the eastern Indo-Nepal border where there is unregulated population movement across the border. The study was conducted at sites in Jhapa District, Nepal and Darjeeling District, India. The study was conducted from August 2003 to February 2004, following the WHO 28 day treatment protocol. The efficacy of chloroquine was tested in India among 91 subjects and of sulfadoxine-pyrimethamine in Nepal among 107 subjects with laboratory-confirmed Plasmodium falciparum malaria. Of the 102 subjects who completed the study in Nepal, there were 21 (20.6%) treatment failures comprising 7 (6.9%) early treatment failures (ETF) and 14 (14.7%) late treatment failures (LTF) (5 late clinical failures [LCF] and 9 late parasitological failures [LPF]). Of the 89 subjects who completed the study in India, there were 46 (51.7%) treatment failures comprising 7 (7.9%) ETFs and 39 (43.8%) LTFs (13 LCFs and 26 LPFs). Based on WHO guidelines both countries need to review their drug policy urgently and make appropriate changes, taking into account aspects of cross-border collaboration in the control of drug-resistant malaria.

Impact of residual spraying of Reldan against Anopheles culicifacies in selected villages of District Ghaziabad (Uttar pradesh), India

BACKGROUND & OBJECTIVES

Indoor residual spraying of Reldan 40% EC @ 0.5 and 1 g/m2 was done in Tatarpur and Chauna villages, respectively in Dhaulana PHC, Distt. Ghaziabad (U.P.) to evaluate its impact against Anopheles culicifacies and malaria incidence. Results were compared with that of Piyawali village which was taken as control area.

METHODS

Four rounds of spray were done from 1999--2000 in human dwellings and cattlesheds in experimental villages. Entomological parameters--man hour density, parity rate, sporozoite rate, etc. were monitored using standard procedures. Epidemiological indicators such as SPR, SFR, cases/000, Pf/000 were also calculated. Cone bioassays as per WHO method were also carried out to assess the persistence of the insecticide on different surfaces.

RESULTS

Entomological results revealed that spraying of reldan @ 0.5 g/m2 resulted in significant reduction in adult densities of An. culicifacies in sprayed villages over the control village. Spraying also resulted in reduction of percent parous females, reduction in malaria incidence (p < 0.05).

INTERPRETATION & CONCLUSION

Reldan showed high efficacy @ 0.5 g/m2 in controlling the densities of An. culicifacies and malaria incidence. However, double dosage of reldan @ 1 g/m2 can be used for comprehensive vector control provided > 95% spray coverage is achieved.

Selection of a highly virulent fungal isolate, Metarhizium anisopliae CLO 53, for controlling Hoplia philanthus

The June beetle, Hoplia philanthus Füessly (Coleoptera: Scarabaeidae), has become a widespread and destructive insect pest of lawns, sport turf, pastures, and horticultural crops in Belgium. The virulence of 34 entomopathogenic fungal isolates from the genera Metarhizium, Beauveria, and Paecilomyces to third-instar H. philanthus was tested in bioassays by dipping larvae in 10(7)conidia/ml suspensions. Two isolates of Metarhizium anisopliae (CLO 53 and CLO 54) caused maximally 90% mortality 10 weeks post-inoculation while other isolates only caused mortalities between 10 and 62%. The virulence of M. anisopliae CLO 53 was further tested by exposing H. philanthus larvae to conidial serial concentrations of 10(4)-10(9)conidia/g sandy soil for up to 11 weeks at 15, 20 or 25 degrees C. Mortality was dependant on the fungal concentration, exposure time, and temperature. Eleven weeks after inoculation, the LC50 values for this isolate ranged from 1.3 to 4.0 x 10(6), 1.0 to 3.2 x 10(5), and 2.5 x 10(4) to 10(5)conidia/g soil at 15, 20, and 25 degrees C, respectively. The LT50 values for this isolate ranged from 3.5 to 21.7, 2.4 to 18.7, and 2.9 to 16.1 weeks at concentrations of 10(9) and 10(4)conidia/g soil at 15, 20, and 25 degrees C, respectively. In glasshouse pot experiment with perennial ryegrass (Lolium perenne L.), the isolate CLO 53 caused mortalities of 50 and 88% of H. philanthus larvae 10 weeks after application of 10(4) and 10(6)conidia/cm(2) soil surface, respectively. The present results suggest that the Belgian isolate CLO 53 has excellent potential for biological control of H. philanthus.

Evaluation of pirimiphos-methyl (50% EC) against the immatures of Anopheles stephensi/An. culicifacies (malaria vectors) and Culex quinquefasciatus (vector of bancroftian filariasis)

BACKGROUND & OBJECTIVES

In India, temephos and fenthion are used as larvicides in fresh and polluted waters. Since use of same insecticide may precipitate resistant, as an alternative bioefficacy of pirimiphos-methyl--an organophosphorus insecticide was evaluated against immatures of Anopheles and Culex species in different breeding habitats in District Ghaziabad (U.P.) and Goa.

METHODS

Laboratory bioassays were carried out using standard WHO procedure. LC50 and LC90 were calculated using Probit analysis. Abbott's formula was used to calculate per cent corrected mortality in laboratory exposures while, Mulla's formula was applied for calculating per cent reduction in mosquito immatures under field conditions.

RESULTS

Pirimiphos-methyl was found to be most effective against larvae of An. stephensi followed by An. culicifacies and Cx. quinquefasciatus. The LC50 and LC90 values against three species were 0.023, 0.032 and 0.04 ppm; and 0.045, 0.057 and 0.114 ppm respectively. In field, pirimiphos-methyl @ 200 g a.i./ha against Anopheles species and @ 300 g a.i./ha against Culex species can produce > 80% reduction in density of immatures up to one week in different habitats. Pirimiphos-methyl < 0.25 ppm is not toxic to fish.

INTERPRETATION & CONCLUSION

Pirimiphos-methyl is more effective against anophelines in clean water than culicines in polluted water. This larvicide should not be used at a concentration above 0.25 ppm in habitats harbouring the larvivorous fish.

Evaluation of repellent action of Cymbopogan martinii martinii Stapf var sofia oil against Anopheles sundaicus in tribal villages of Car Nicobar Island, Andaman & Nicobar Islands, India

A field study was carried out to evaluate the mosquito repellent action of Cymbopogan martinii martinii Stapf var sofia oil in tribal village of Car Nicobar Island. Results revealed that application of 1 ml of the oil provided 98.7% protection in indoor and 96.52% in outdoor conditions during 12 h period of observation from the bites of An. sundaicus. Cymbopogan martinii martinii Stapf var sofia oil is an indigenous product, its application is safe and can be widely used for protection from malaria.

Prevalence of the K76T mutation in the pfcrt gene of Plasmodium falciparum among chloroquine responders in India

Chloroquine-resistant Plasmodium falciparum needs to be monitored in the field for effective malaria control strategies. A point mutation K76T in the P. falciparum chloroquine resistance transporter (Pfcrt) protein has recently been proposed as a molecular marker for the faster detection of chloroquine-resistant falciparum malaria in field. We describe here the evaluation of this marker in Indian P. falciparum isolates. A total of 274 Indian P. falciparum isolates were analyzed for the K76T mutation. This mutation was detected in all the clinical isolates obtained from the in vivo chloroquine non-responders. But majority of the clinical isolates from chloroquine responders (71 of 74 patients, i.e. 96%) also harbored this mutation. The K76T mutation was indeed highly prevalent (91%) among 213 clinical isolates. There was a significant association between K76T mutation and the in vitro chloroquine response (P<0.05) but six isolates showed discordant results. In conclusion, the K76T mutation fails to differentiate majority of the chloroquine responders from that of the non-responders and thus will be of limited use in the field in India.

Bio-efficacy and operational feasibility of alphacypermethrin (Fendona) impregnated mosquito nets to control rural malaria in northern India

Bio-efficacy and operational feasibility of alphacypermethrin treated nets was evaluated in certain villages of District Ghaziabad (U.P.). Results revealed that poly-filament nylon nets treated with alphacypermethrin suspension concentrate (g/l) formulation @ 25 mg/m2 has shown repellent action (26.5 +/- 8.1), excito repellent action (93.7 +/- 8.1) and killing action (100%) against An. culicifacies landed on treated nets. Significant reduction in indoor resting density of An. culicifacies in human dwellings was also observed in treated nets village (p < 0.05). Instant killing action of treated nets did provide complete protection to inhabitants sleeping inside the net from An. culicifacies bites. The persistent use of nets by the inhabitants has also resulted significant reduction in malaria cases (p < 0.05). It was interesting to note that not even a single case of falciparum malaria was observed after distribution of treated nets in spite of the fact that at no point of time cent per cent compliance of net usage was observed during the study period. Bio-assay tests revealed that treated nets can produce up to 70% mortality in An. culicifacies for about 22 weeks and as such only one treatment with insecticide is required in a year in seasonal transmission area to protect from malaria. The study also revealed that treated nets can be stored at room temperature for about 10 months without loosing their efficacy suggesting thereby that malaria outbreaks can be tackled by the nets if adequate treated nets are stored in core problem districts. It was also revealed that An. culicifacies is a late night biter and as such treated nets can be used successfully against this species.