Understanding Behavioural Temperament of Phlebotomus argentipes Under the Influence of DDT-IRS Versus SP-IRS for Scoping New Approaches for Maximum Control Over the VL-Vector Population in Bihar

Background:After the decades of Dichlorodiphenyltrichloroethane (DDT) use, Phlebotomus argentipesreportedly developed resistance against it affecting every aspect of vector control at grass-root level. Although DDT based Indoor Residual Spray (IRS) has been replaced with Alphacypermethrine-a Synthetic Pyrethroid (SP) based insecticide, since 2016 butits successful implementation at the Visceral Leishmaniasis (VL) endemic regime of Bihar doesn’t cause much effect upon VL vector density. Furthermore, the outcomes of existing operational research works, it Original ResearchArticle had been observed that VL vectors are continuously changing its behavior under the pressure of insecticides. Methods: For validating the hypothesis, present study has been carried out at Vaishali and Patna being highly and semi-endemic sites respectively for quantifying the oriental behavior among VL vectors persuaded by the IRS and enforce them to remain alive and get trapped in light trap even after changed chemical composition of IRS i.e., SP-IRS from routine DDT-IRS. Results:Following results, a significant reduction in sand fly density (i.e., 33.09% and 29.16%) was observed for outdoor and indoor caught sand flies, collected with light trap and aspirator respectively. Significant higher no. of sand fly collection in terms of per light traps per night was recorded from the outdoor sites than thosefrom indoor habitat for each village of Vaishali and Saran district of Bihar. Higher no. of male sand flies than to that of female ones were collected from outdoor sites and only unfed female sand flies (i.e., 100%) were caught following SP-IRS from each study villages of Vaishali and Saran districts of Bihar.Conclusions:The results of higher no. of sand flies collection from the outdoor sites as compared with the indoor habitat validate the hypothesis of gradual shifting of habitat of VL vectors from endophilic to exophilic which is undoubtedly followed due to the fact of developed resistance among them against chemical constituent of IRS. Results provide very useful information about the sand fly dynamics under the impact of IRS and accordingly, advocates the combined approach of IRS along with insecticidal fogging together at a same time that could be an effective dividend for maximum VL vector control along for negotiating VL cases at par for longer duration during the maintenance phase at the VL foci.

Determination of 666 and DDT pesticide residues in Anoectochili Roxburghii Gemma Terminalis by gas chromatography / 中草药

Objective: Determination of 666 (BHC) and DDT residues in Anoectochili Roxburghii Gemma Terminalis. Methods: Using gas chromatography (GC) for limited detecting the eight kinds of organochlorine pesticide residues, such as BHC (α-BHC, β-BHC, γ-BHC, and δ-BHC) and DDT (PP '-DDE, PP'-DDD, OP '-DDT, and PP'-DDT) in Anoectochili Roxburghii Gemma Terminalis. Results: Linear BHC and DDT standard curve were good, the correlation coefficient was 0.9988-0.9997, the average recovery rates were 95.4%-98.9%, 1%-2.98% RSD. The detection limitation was 0.0053-0.021 g/L. Result of Chinese herbal medici: β-BHC for G 0.0009mg/kg(Among them, α-BHC, γ-BHC, δ-BHC, PP'-DDE, OP'-DDT, PP'-DDD, PP'-DDT not detected) Conclusion: The method is accurate, reliable, scientific, and feasible, and has higher sensitivity and linear range, which can be used for quality control of pesticide residues in water.

Multiple insecticide resistances and kdr mutation of Culex pipiens pallens in north-central Anhui Province / 中国血吸虫病防治杂志

Objective To understand the status of resistance to multiple insecticides and the frequencies of kdr mutations in Culex pipiens pallens from north?central Anhui Province. Methods From July to September,2014,the C. pipiens pallens mosquito larvae were collected in Huaibei,Bengbu and Chuzhou cities of the north?central Anhui Province and reared to adults. The female adult mosquitoes at 3-5 days post emergence were tested for susceptibility to the four insecticides,namely 0.05%deltamethrin,5%malathion,0.1%bendiocarb and 4%DDT,by using the standard WHO resistance tube bioassay. The detec?tion of the point mutations of the kdr gene at codon 1014 was conducted by PCR and DNA sequencing in the deltamethrin?resis?tant and?susceptible mosquitoes. Results High levels of resistance to all the four insecticides were found in all the three tested populations,although mosquito mortality varied among populations and test insecticides. Among the test insecticides,DDT showed lowest mortality with no significant difference(F=1.027,P>0.05)in all test populations,whereas significantly differ?ent mortalities were observed among populations for the remained three insecticides tested(deltamethrin,malathion,and ben?diocarb)(F = 23.823,33.955,128.841;all P < 0.01). Two types of non?synonymous kdr mutation at codon position 1014 (L1014F and L1014S)were observed. A positive correlation between L1014F mutation frequencies and deltamethrin resistance levels were detected in the three mosquito populations(r2=0.718,P<0.01). Conclusions The observed high levels of resis?tance to multiple?insecticides coupled with the occurrence of medium to high kdr frequencies in populations of C. pipiens pallens could profoundly affect the mosquito vector control programme in China. The local health departments need to strengthen vector dynamic monitoring and implement rational resistance management strategies.

U.S. Military Administration's Malaria Control Activities (1945-1948) / 의사학

To prevent and control infectious diseases was one of the major concerns of U.S. military government when they stationed in Korea in 1945. It was because the spread of various infectious diseases can cause social unrest and they can also affect the U.S. military. Malaria was one of the most important infectious diseases to which the U.S. military had been paying special attention. The U.S. military received a severe damage during the Pacific war with Japan due to malaria. It was said that more soldiers were lost by malaria than by battle itself. The bitter experience they had during the war made them accumulate more systematic and practical knowledge against malaria. As a result, by the end of the war, the U.S. military could run more than hundreds of units specialized in controlling malaria. Thanks to such a preparation, they could immediately begin their anti-malaria activities in Korea soon after the World War II. Although the vivax malaria, which is the dominant type in Korea, is not as much a fatal type as that in the Pacific areas, it was damaging enough to the infected. The 207th Malaria Survey Detachment carried out collecting and identifying the kinds of mosquitos in Korea. In addition, they also surveyed the prevalence of malaria among school children in Seoul. In terms of controlling malaria, DDT played a decisive role. Vector control is the most effective and ideal measurements against malaria. Before the development of DDT, it was practically impossible to eradicate mosquitos which arise from extremely broad areas. However, DDT could not be used as it had been expected in the rural area, because spraying DDT in the rice paddies which is the breeding place of mosquitos kills rice. Despite such a limitation in anti-malaria activities of the US military government, it should be noted that a significant turn in controlling malaria was possible thanks to the development of DDT.

Una deuda del pasado: efectos de los organoclorados en trabajadores del programa de control de vectores - Colombia / A debt from the past: effects of organochlorines in workers of vector control program - Colombia

Introducción: En Colombia se supone no se usan organoclorados debido a la ratificación de la Convención de Estocolmo y el Convenio de Rotterdam, que prohíben el uso de este tipo de sustancias. Objetivo: Evaluar la exposición a plaguicidas organoclorados empleados en salud publica en la población trabajadora del programa de control de vectores en Colombia en 2013. Métodos: Se realizó un estudio descriptivo de corte transversal en el grupo de trabajadores del programa de control de enfermedades transmitidas por vectores. A todos los participantes se aplicó un cuestionario estandarizado para recolectar variables sociodemográficas, ocupacionales, clínicas y toxicológicas. Se determinaron los niveles de 13 organoclorados en suero mediante cromatografía de gases en el Instituto Nacional de Salud de Colombia. Resultados: El reporte de manipulación de insecticidas organoclorados fue del 39,1%. El 100% de los trabajadores que usaron organoclorados refirieron el uso DDT. El 7,5% refirieron el uso de Aldrin. El 100% de los trabajadores refirió ausencia de elementos de protección individual durante la manipulación de clorados. Los organoclorados con niveles más altos fueron 4,4- DDT y α -HCH. Los síntomas de mayor presentación fueron: cefalea 28,7%, mareo 29,9%, disminución de fuerza en miembros superiores 17,2% y síntomas neuropsiquiátricos 24%. Se encontró una asociación entre la exposición laboral a DDT y síntomas neuropsiquiátricos. Conclusiones: El promedio de DDT en sangre de los trabajadores en Colombia son superiores a los reportados en la literatura. Los hallazgos de síntomas neuropsiquiátricos y la exposición laboral a organoclorados concuerdan con los reportes de la literatura.

Introduction: It is assumed that in Colombia organochlorides are not used due to the ratification of the Stockholm Convention and the Rotterdam Convention, forbidding the use of those substances. Objective: To evaluate exposure to organochloride pesticides used in the working population of the vector control program in Colombia, 2013. Methods: A descriptive cross-sectional study was performed in the group of workers from the vector-borne disease management program. To all participants were applied a standardized questionnaire to collect sociodemographic, occupational, clinical and toxicological variables. Thirteen organochloride levels in serum were measured by gas chromatography at the National Institute of Health of Colombia. Results: The report show using of organochloride insecticides in the 39.1%. One hundred percent of the workers who used organochlorides reported use of DDT. 7,5% reported use of aldrin. One hundred percent or the workers referred the absence of elements of personal protection when implementing chlorinated compounds. Organochlorides with higher levels were 4,4- DDT y α -HCH. The most common symptoms were: headache 28.7%, dizziness 29.9%, decreased strength in upper limbs 17.2% and neuropsychiatric symptoms 24%. An association between occupational exposure to DDT and neuropsychiatric symptoms were found. Conclusions: The average of DDT in blood of workers in Colombia is higher than those reported in the literature. Findings of neuropsychiatric symptoms and occupational exposure to organochloride are consistent with literature reports.

DDT & deltamethrin resistance status of known Japanese encephalitis vectors in Assam, India.

Background & objective: Japanese encephalitis (JE) outbreaks are common in Assam, northeastern State of India. Information on resistance in known JE vectors in the affected area is important for effective control measures. This study was undertaken to determine the species abundance of JE vectors endemic to Sibsagar district of Assam, and their susceptibility against DDT and deltamethrin. Methods: Adult mosquitoes were collected using CDC light trap and aspirators from human dwellings from 13 endemic villages falling under three Primary Health Centres. Collected mosquitoes were identified and unfed female mosquitoes were used for DDT and deltamethrin sensitivity bioassay. The bioassay was performed following WHO protocol using standard susceptibility test kit. Knockdown time (KDT) was monitored at every 10 minutes intervals, whereas mortalities were recorded 24 h post-exposure. Vector density and resistance status were mapped using geographic information system (GIS) technique. Results: A total of 7655 mosquitoes were sampled under three genera, i.e. Anopheles, Culex and Mansonia, and nine species, the JE vector Cx. vishnui group (31.78%) was the most predominant species, followed by Ma. uniformis (16.81%) and Ma. indiana (16.45%). All vector species were suspected to be resistant to DDT and sensitive to deltamethrin, except Ma. indiana, which was suspected to deltamethrin resistant. The KDT50 and KDT95 values of vector mosquitoes for DDT were significantly higher as compared to deltamethrin. The probit model used to estimate KDT50 and KDT95 values did not display normal distribution of percentage knockdown with time for all the vectors tested for DDT and deltamethrin, except for Ma. indiana for deltamethrin assay and Cx. gelidus for the DDT assay. Interpretation & conclusion: Differences in insecticide resistance status were observed between insecticides and vector species. The results of this study provided baseline data on insecticide resistance in known JE vectors of Sibsagar, Assam. The maps generated may allow better communication in control operations and comparison of changes in susceptibility status of these vectors over time.

Paradigmas de control de la malaria en Guatemala, siglos XX y XXI, de la erradicación a la eliminación / Paradigms of the malarial control in Guatemala in the 20th and 21st centuries moving from eradication to elimination

La malaria continúa siendo un problema de salud pública mundial. Durante los siglos XX y XXI el abordaje de esta enfermedad sufrió cambios paradigmáticos muy interesantes, pero principalmente estuvo influenciado por los descubrimientos relacionados con la segunda guerra mundial, la situación económica mundial, el advenimiento de nuevas estrategias de control y el abordaje de la enfermedad por medio de la participación comunitaria y el sector de la salud. El propósito de este trabajo es presentar los cambios de paradigmas desde una óptica vertical o erradicación, a una horizontal o eliminación, y desde lo positivista cuantitativo a lo mixto, en el abordaje de la malaria en Guatemala. Se realiza una reseña histórica de la malaria y se discuten los aspectos bioéticos del uso del insecticida dicloro-difenil-tricloroetano a nivel mundial. En los países desarrollados fueron justificadas las intervenciones de erradicación con el rociamiento intradomiciliar del insecticida citado y completarlas con el diagnóstico y tratamiento de la malaria; la realidad en la mayoría de los países en vías de desarrollo, fue diferente, puesto que no pudieron mantener los programas de erradicación por problemas financieros, un ejemplo claro de iniquidad global. Guatemala en esta década trabaja en la fase de preeliminación-eliminación, con buenos resultados, lo que marca un cambio de paradigma e indica que las medidas contra la malaria deben ser horizontales y favorecer el trabajo intra e intersectorial.

Malaria remains a world health problem. During the 20th and 21st centuries, the approach to this disease underwent very interesting paradigmatic changes, but they were influenced by breakthroughs derived from the Second World Wear, the international economic situations, the advent of new monitoring strategies and the approach to the disease based on the community and the health sector involvement. The objective of this paper was to present changes in paradigms form a vertical perspective or eradication to a horizontal viewpoint or elimination, and from a quantitative positivist to a combined standpoint in addressing malaria in Guatemala. A historical account of malaria was made and the bioethical aspects of the use of dichlorodiphenyltrichloroethane worldwide were discussed. The eradicating interventions by using the insecticidal spraying of houses were backed up in the developed countries. This was supplemented with the diagnosis and treatment of malaria. However, the situation was different in most of the developing countries, since their financial restrictions did not make possible to keep the eradication programs, being a clear example of the global inequality. In the present decade, Guatemala is going through the pre-elimination-elimination phase and it works with good results, which is indicative of a change in paradigm and shows that actions against malaria should be horizontal in order to encourage the intrasectorial and the intersectorial work.

Sensibilidad de Anopheles darlingi Root 1840 a insecticidas, en dos localidades de los departamentos de Santander y Caquetá, Colombia / Susceptibility to insecticides of Anopheles darlingi Root 1840, in two locations of the departments of Santander and Caquetá, Colombia

Introducción. La sensibilidad fisiológica a los insecticidas usados en salud pública es el principal factor que se debe tener en cuenta en la selección de las estrategias de control en los vectores de malaria. Objetivo. Determinar el estado de sensibilidad fisiológica de Anopheles darlingi a insecticidas, en dos localidades de los departamentos de Santander y Caquetá. Materiales y métodos. Se recolectaron hembras silvestres de An. darlingi y se hicieron bioensayos según la metodología de la Organización Mundial de la Salud (OMS, 1981) y de los Centers for Disease Control and Prevention (CDC, 1998), usando moléculas insecticidas grado técnico. Resultados Las poblaciones naturales de An. darlingi de las veredas Gerumano en Solano (Caquetá) y la vereda Las Margaritas en San Vicente de Chucurí (Santander) mostraron sensibilidad a los insecticidas piretroides lambdacialotrina y deltametrina, al organoclorado DDT y al organosofosforado fenitrotión, con mortalidades del 100 % en todas la pruebas del CDC y entre 95 y 100 % para las de la OMS. Para el carbamato propoxur, la mortalidad de 88 % en la población de Gerumano, evaluada por las pruebas de la OMS, coincide con valores de vigilancia para esta molécula. Conclusión. Los productos químicos que tienen como ingrediente activo las moléculas evaluadas, son eficaces para el control de An. darlingi en los sitios de estudio.

Introduction. Physiological resistance to insecticides used in public health is the main factor to define strategies for malaria vector control. Objective. To determine the physiological status of insecticide susceptibility of natural populations of An. darlingi from two localities in the Santander and Caquetá departments. Materials and methods. Wild adult Anopheles darlingi females were collected and bioassays using technical grade insecticides were performed following the methods recommended both by the World Health Organization (WHO, 1981) and the Centers for Diseases Control and Prevention (CDC, 1998). Results. The natural populations of An. darlingi from the villages of Gerumano, Solano, Caqueta and Las Margaritas, San Vicente de Chucurí, Santander, showed susceptibility to the pyrethroids lambdacyhalothrin and deltamethrin, to the organochlorate DDT and to the organophosphate fenitrothion with 100% mortality rates in all of the CDC tests and between 95 and 100% in the tests performed following the WHO methods. For the carbamate propoxur the 88% mortality rate obtained in the village of Gerumano following the methods recommended by WHO coincides with the surveillance methods established for surveillance of this molecule. Conclusions. Chemical products whose active ingredients are the molecules tested are effective for control of An. darlingi in the study sites.

Impact of changing over of insecticide from synthetic pyrethroids to DDT for indoor residual spray in a malaria endemic area of Orissa, India.

Background & objectives: Development of insecticide resistance in malaria vectors has been a major problem for achieving effective vector control. Due to limited availability of insecticides, the only option is management of resistance by judiciously using the insecticides and rotating them to maintain their effectiveness. This study was carried out in a malaria endemic area of Sundergarh district in Orissa where synthetic pyrethroids (SP) were in use for the last couple of years. The change-over from SP to DDT was done in one arm of study, and the other two arms remained on SP and insecticide-treated nets (ITN). Entomological and parasitological monitoring was done to assess the impact. Methods: The study design comprised of three arms (i) two rounds of indoor residual spraying (IRS) with DDT 1g/m2 as a change-over insecticide in areas previously under synthetic pyrethroids; (ii) two rounds of IRS with synthetic pyrethroid (alphacypermethrin, ACM) @ 25 mg/m2; and (iii) an unsprayed area under ITN/long lasting insecticide nets (LNs). Indoor residual spraying was undertaken under strict supervision to maintain quality and coverage. Contact bioassays were conducted to know the persistence of insecticide on sprayed surfaces and adult vector density was monitored in fixed and randomly selected houses. Malaria incidence was measured through fortnightly domiciliary surveillance under primary health care system in all the study villages. Results: The insecticide susceptibility tests showed that An.culicifacies was resistant to DDT but susceptible to malathion and ACM. However, An. fluviatilis was susceptible to all the three insecticides. ACM was effective in killing An. culicifacies on mud and wooden sprayed surfaces and maintained effective bioefficacy ranging from 92 to 100 per cent up to five months, whereas DDT failed to achieve effective mortality in An.culicifacies. However, there was significant decline in the density of An.culicifacies in ACM and DDT areas in comparison to ITNs/LNs. There was 61 per cent reduction in the slide positivity rate in ACM area in comparison to 48 and 51 per cent in DDT and ITN/LNs areas, respectively. The adjusted incidence rate of malaria cases per 1000 population in three study areas also showed significant declines within each group. Interpretation & conclusions: The present findings show that the change-over of insecticide from synthetic pyrethroids to DDT brings about the same epidemiological impact as envisaged from continuing SP spray or distributing insecticide treated nets/long-lasting insecticidal nets provided there is a good quality spray and house coverage.

Global status of DDT and its alternatives for use in vector control to prevent disease: [review] / Estado global do DDT e suas alternativas para utilização no controle de vetores para prevenção de doenças: [revisão]

Neste artigo, revisei o estado do dicloro-difenil-tricloroetano (DDT) utilizado no controle de doenças causadas por vetores, e seus benefícios e riscos em relação às alternativas disponíveis. Dados atuais sobre o uso de DDT foram obtidos através de questionários e relatórios, assim como uma busca Scopus para resgatar artigos publicados. Quase 14 países utilizam DDT para controle de doenças, e diversos outros o estão reintroduzindo. A preocupação sobre o uso contínuo de DDT é abastecida por relatórios recentes dos altos níveis de exposição humana associada com a pulverização em recintos fechados, acumulando evidências sobre efeitos crônicos a saúde. Existem sinais de que mais vetores da malária estão se tornando resistentes à ação tóxica do DDT. Métodos químicos efetivos estão disponíveis como alternativas imediatas ao DDT, mas o desenvolvimento da resistência está diminuindo a eficácia das ferramentas de insetização. Métodos não químicos são potencialmente importantes, mas sua efetividade no programa necessita de estudos urgentes. O controle integrado de vetores fornece uma estrutura para o desenvolvimento e a implementação de tecnologias e estratégias efetivas como alternativas sustentáveis à dependência ao DDT.

In this article I reviewed the status of dichlorodiphenyltrichloroethane (DDT), used for disease vector control, and its benefits and risks in relation to the available alternatives. Contemporary data on DDT use were obtained from questionnaires and reports as well as a Scopus search to retrieve published articles. Nearly 14 countries use DDT for disease control, and several others are reintroducing DDT. Concerns about the continued use of DDT are fueled by recent reports of high levels of human exposure associated with indoor spraying amid accumulating evidence on chronic health effects. There are signs that more malaria vectors are becoming resistant to the toxic action of DDT. Effective chemical methods are available as immediate alternatives to DDT, but the development of resistance is undermining the efficacy of insecticidal tools. Nonchemical methods are potentially important, but their effectiveness at program level needs urgent study. To reduce reliance on DDT, support is needed for integrated and multipartner strategies of vector control. Integrated vector management provides a framework for developing and implementing effective technologies and strategies as sustainable alternatives to reliance on DDT.

Bedbugs (Cimicidae infestation): the worldwide renaissance of an old partner of human kind

Bedbugs have been known as a human parasite for thousands of years, but scientific studies about this insect are recent and limited. Cimex lectularius, the common bedbug, was a well-known parasite in human dwellings until the end of the Second World War. Nowadays, bedbugs are considered uncommon in the industrialized world. Anecdotal reports suggest that bedbugs are getting more common in the United States, Canada, and United Kingdom. In Brazil, there are few reports about bedbug infestations in the literature. The aim of this article was to alert physicians, especially in Brazil, about this ectoparasitosis, including aspects of the bedbug biology, their parasitism in human host, treatment and prophylaxis.

Persistence of DDT, malathion & deltamethrin resistance in Anopheles culicifacies after their sequential withdrawal from indoor residual spraying in Surat district, India.

Background & objectives: Under the national antimalaria programme DDT was introduced in early 1950s for vector control and later hexachloro cyclohexane (HCH) followed by malathion and recently synthetic pyrethroids in 1990s to manage the insecticide resistance in Anopheles culicifacies. Subsequent replacement led to development of multiple resistances in An. culicifacies in Surat district in Gujarat State. Indoor residual spray (IRS) was completely withdrawn in southern villages in Surat in 2002. This study was undertaken in these areas to study the persistence of resistance to DDT, malathion and deltamethrin after sequential withdrawal of IRS with these insecticides at different times. Methods: Susceptibility tests on An. culicifacies were conducted using standard WHO methods and kits. Mortality, knockdown time and lethal times were calculated for An. culicifacies exposed to WHO prescribed diagnostic concentrations of different insecticide impregnated papers. Results: Persistence of DDT-resistance was observed even after 30 yr of its withdrawal from IRS. Similarly, persistence of malathion resistance was also observed after 9 yr of its withdrawal from IRS, while reversal of deltamethrin-resistance was observed very fast within 2-3 yr after its withdrawal from IRS in 2002. Interpretation & conclusion: Present data indicate that the quantum of reversion of insecticide resistance in a population is relative and depends on the genetic stability of the respective resistance genes in the mosquitoes. In the present study withdrawal of pyrethroid-IRS resulted in increased susceptibility against pyrethroids alone and was independent of existence of resistance to insecticides of other groups. This study emphasizes that appropriate rotation of different insecticides; including carbamates may prevent or delay the onset of resistance.

Co-metabolism of DDT by the newly isolated bacterium, pseudoxanthomonas sp. wax

Microbial degradation of 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (DDT) is the most promising way to clean up DDT residues found in the environment. In this paper, a bacterium designated as wax, which was capable of co-metabolizing DDT with other carbon sources, was isolated from a long-term DDT-contaminated soil sample by an enrichment culture technique. The new isolate was identified as a member of the Pseudoxanthomonas sp., based on its morphological, physiological and biochemical properties, as well as by 16S rRNA gene analysis. In the presence of 100 mg l-1 glucose, the wax strain could degrade over 95 percent of the total DDT, at a concentration of 20 mg l-1, in 72 hours, and could degrade over 60 percent of the total DDT, at a concentration of 100 mg l-1, in 144 hours. The wax strain had the highest degradation efficiency among all of the documented DDT-degrading bacteria. The wax strain could efficiently degrade DDT at temperatures ranging from 20 to 37ºC, and with initial pH values ranging from 7 to 9. The bacterium could also simultaneously co-metabolize 1,1-dichloro-2,2-bis(p-chlorophenyl)ethane (DDD), 2,2-bis(p-chlorophenyl)-1,1-dichlorethylene (DDE), and other organochlorine compounds. The wax strain could also completely remove 20 mg kg-1 of DDT from both sterile and non-sterile soils in 20 days. This study demonstrates the significant potential use of Pseudoxanthomonas sp. wax for the bioremediation of DDT in the environment.

Susceptibilidad de Aedes aegypti a DDT, deltametrina y lambdacialotrina en Colombia / Susceptibility of Aedes aegypti to DDT, deltamethrin, and lambda-cyhalothrin in Colombia

OBJETIVOS: Evaluar el estado de susceptibilidad a insecticidas piretroides deltametrina y lambdacialotrina y al organoclorado DDT, e identificar los mecanismos bioquímicos asociados con resistencia en 13 poblaciones naturales de Aedes aegypti recolectadas en localidades de Colombia donde el dengue es un grave problema de salud pública. MÉTODOS: Se recolectaron y criaron en condiciones controladas formas inmaduras de diferentes criaderos naturales del vector para cada localidad. Con la generación F2 se realizaron bioensayos utilizando las metodologías OMS 1981 (papeles impregnados) y CDC 1998 (botellas impregnadas). En las poblaciones con mortalidades compatibles con disminución de la susceptibilidad, se midieron los niveles de esterasas no específicas (ENE), oxidasas de función mixta (OFM) y acetilcolinesterasa modificada (ACEM) mediante pruebas colorimétricas. RESULTADOS: Todas las poblaciones del mosquito evaluadas evidenciaron resistencia al organoclorado DDT. En cuanto a los piretroides, se encontró resistencia generalizada a lambdacialotrina pero no a deltametrina. Los mecanismos bioquímicos de resistencia evaluados permitieron encontrar 7 de 11 poblaciones con ENE elevadas y una población con OFM incrementadas. CONCLUSIONES: Se descarta la resistencia cruzada de tipo fisiológico entre el DDT y lambdacialotrina en las poblaciones de A. aegypti evaluadas. La resistencia fisiológica a lambdacialotrina parece asociarse con el incremento de las ENE. El comportamiento diferencial en los niveles de susceptibilidad y los valores enzimáticos entre poblaciones se asociaron con la variabilidad genética y presión de selección química a nivel local.

OBJECTIVES: To assess the susceptibility status of 13 natural populations of Aedes aegypti (collected from sites in Colombia where dengue is a serious public health problem) to the pyrethroids, deltamethrin and lambda-cyhalothrin, and to the organochlorine, DDT, and to identify any biochemical mechanisms associated with resistance. METHODS: Immature forms of the vector were collected from natural breeding spots at each site and then raised under controlled conditions. Using the F2 generation, bioassays were performed using the World Health Organization's 1981 methodology (impregnated paper) and United States Centers for Disease Control and Prevention's 1998 methodology (impregnated bottles). In populations where mortality rates were consistent with decreased susceptibility, levels of nonspecific esterases (NSE), mixed-function oxidases (MFO), and acetylcholinesterase (AChE) were measured using colorimetric tests. RESULTS: All of the mosquito populations that were tested showed resistance to the organochlorine DDT. In the case of the pyrethroids, widespread resistance to lambda-cyhalothrin was found, but not to deltamethrin. Assessing the biochemical resistance mechanisms showed that 7 of the 11 populations had elevated NSE, and one population, increased MFO. CONCLUSIONS: Physiological cross-resistance between DDT and lambda-cyhalothrin in the A. aegypti populations tested was dismissed. Physiological resistance to lambda-cyhalothrin appears to be associated with increased NSE. The differences in susceptibility levels and enzyme values among the populations were associated with genetic variations and chemicals in use locally.

Trends of poisoning in Faridkot region of Punjab- A retrospective study of one year.

Since immemorial times, poisonous substances have been reported to be adversely affecting human life, both in terms of morbidity and mortality. Evolution in fields like agriculture, industry etc has made wide and easy availability of various poisonous substances. The present study is a retrospective study of one year which is related to poisoning cases that were admitted in the emergency department of G.G. S. Medical College, Faridkot from 1st January 1996 to 31st December 1996. The analysis of the data revealed that out of 78 patients admitted in the hospital, 31 patients died. The maxi-mum incidence was seen in the age group of 21-30 years with males outnumbering the females. The commonest poison used was organophosphorus group of compounds.

Study on the levels of serum organochlorine pesticides residues in breast cancer patients from Tangshan areas / 中国综合临床

Objective To evaluate the levels of serum organochlorine pesticide residues in breast cancer patients and benign breast disease patients from Tangshan areas. Methods One hundred fifty-eight breast cancer patients and 129 benign breast disease patients from two districts of TangShan were entrolled in the study. The levels of serum organochlorine pesticides ( DDTs and HCHs) were detected through gas chromatography/electron capture. Spearman's rank correlation was used between age, BMI and the level of serum organochlorine pesticide residues in patients. Results The serum levels of a-HCH, p-HCH and PP'-DDE between breast cancer patients and benign breast disease patients were statistically different(P <0. 05). The serum levels of p-HCH and PP'-DDE were positively correlated with age and BMI in both groups, with correlation coefficients of 0. 272 and 0. 330 for age and 0. 207 and 0. 313 for BMI in the breast cancer patients,as well as correltion coefficients of 0. 339 and 0. 260 for age and 0. 227 and 0. 209 for BMI in the benign breast disease patients. Conclusions The levels of organochlorine pesticide residues in serum in breast cancer patients were higher than those in benign breast disease patients and were positively correlated with age and BMI. The results offer more information to the pathogenesis, prevention and control measures of breast cancer.

Vector density and the control of kala-azar in Bihar, India

Bihar, India has been in the grip of kala-azar for many years. Its rampant and severe spread has made life miserable in most parts of the state. Such conditions require a comprehensive understanding of this affliction. The numbers coming out of the districts prone to the disease in the north and south Ganges have provided us with several startling revelations, as there are striking uniformities on both sides, including similar vegetation, water storage facilities, house construction and little change in risk factors. The northern areas have been regularly sprayed with DDT since 1977, but eradication of the disease appears to be a distant dream. In 2007 alone, there were as many as 37,738 cases in that region. In contrast, the southern districts of Patna and Nalanda have never had the disease in its epidemic form and endemic disease has been present in only some pockets of the two districts. In those cases, two rounds of spraying with DDT had very positive results, with successful control and no new established foci. In addition, an eleven-year longitudinal study of the man hour density and house index for the vector Phlebotomus argentipes demonstrated that they were quite high in Patna and Nalanda and quite low in north Bihar. Given these facts, an attempt has been made to unravel the role of P. argentipes saliva (salivary gland) in the epidemiology of kala-azar. It was determined that patchy DDT spraying should be avoided for effective control of kala-azar.

A report on the indoor residual spraying (IRS) in the control of Phlebotomus argentipes, the vector of visceral leishmaniasis in Bihar (India): an initiative towards total elimination targeting 2015 (Series-1).

Background & objectives: Visceral leishmaniasis, commonly known as kala-azar is endemic in Bihar state, India. Current vector control programme in Bihar focuses mainly on spraying the sandfly infested dwellings with DDT. The Government of India in collaboration with WHO has fixed the target 2015 for total elimination of kala-azar. The present study was carried out to see the impact of DDT and improved IEC in the containment of vector density vis-à-vis disease transmission. Methods: Before the start of the spraying operations training was imparted to all the medical and paramedical personnel regarding the methods of spraying operations. Pre- and post-sandfly density was monitored in four selected districts. Incidences of kala-azar cases were compared for pre- and post-spray periods. Social acceptability and perceptions of households was collected through questionnaires from 500 randomly selected households in the study districts. Results: House index in three study districts reduced considerably during post-spray when compared to pre-spray. Kala-azar incidence in many districts was reduced after the DDT spray. Either partial or complete refusal was reported in 14.4%, while 35% were not satisfied with the suspension concentration and coverage; and 46.6% were found satisfied with the spraying procedure. Interpretation & conclusion: Strengthening the IEC activities to sensitise the community, proper training of health personnel, monitoring of spray, good surveillance, proper treatment of cases and two rounds of DDT spray with good coverage in the endemic districts up to three years are essential to achieve the desired total elimination of kala-azar in Bihar state.

Knowledge About Sandflies in Relation to Public and Domestic Control Activities of Kala-azar in Rural Endemic Areas of Bihar.

Visceral Leishmaniasis (VL) control is a global cause of concern. To identify the gaps in People's knowledge/ awareness about sand flies and control activities of kala-azar in rural endemic areas of Bihar, this study consisting of 450 respondents with 288 male and 162 female was carried out. The result showed that 95% respondents had heard about the disease up to some extent, but majority respondents were neither aware about the vector of kala-azar, nor they had any idea about transmission of the disease. About 61% had wrong impression that mosquitoes were causing kala-azar. Regarding knowledge about breeding and resting sites of vectors, 20% reported cattle shed, 16% crevices in the household followed by 15% damp dark places. The attitude of respondents towards vector control programme was poor, as 99% lost faith in the DDT spraying because of ineffectiveness, like no reduction in mosquito nuisance. Bed net was considered the best protection method against sand fly or mosquito nuisance but the cost was considered the major constraint in its use. Proper health education programme in Simple and local language along with visual demonstration should be promoted to enhance the awareness and co-operation at community level.