Seasonal prevalence & resting behaviour of Anopheles minimus Theobald & An. fluviatilis James (Diptera: Culicidae) in east-central India.

Background & objectives: Anopheles minimus has recently been reported to have re-appeared in Keonjhar district of Orissa after a period of about 45 years of launching the malaria eradication programme. An. minimus and An. fluviatilis were the incriminated major malaria vectors in the district, endemic for falciparum malaria. The information on seasonal prevalence and resting behaviour of the vectors is crucial for implementing appropriate malaria control measures. Therefore, a study was undertaken on seasonal prevalence and resting behaviour of An. minimus and An. fluviatilis in this district. Methods: Seven randomly selected villages of Keonjhar district, Orissa, were studied during August 2005 to November 2007. Daytime resting collections indoors and outdoors were made covering three seasons of the year. The Anopheles mosquitoes obtained from different habitats were identified. Collections were maintained separately according to different sites as well as heights of the walls in human dwellings. Results: Among the indoor collections, the densities of An. minimus and An. fluviatilis were higher in human dwellings than cattle sheds. An. fluviatilis was the predominant (41.5%) species followed by An. minimus (26.3%) in human dwellings. The density of both the vector species in human dwellings peaked during rainy and winter seasons followed by summer. Walls were the most preferred site by these vectors for resting and the maximum number was collected at a height of 3 to 4 ft. Interpretation & conclusions: The resting behaviour of the vector species increases their contact with the sprayed walls and therefore, a quality residual spraying of human dwellings focusing indoor walls could interrupt the malaria transmission in this area.

Seasonal fluctuations in prevalence of dog intestinal parasites in public squares of Mar del Plata city, Argentina and its risk for humans / Estacionalidad en la prevalencia de parásitos intestinales caninos en plazas públicas de Mar del Plata, Argentina, y su riesgo para la salud humana

The aim of this work is to analyze whether there is a seasonal prevalence of parasites in dog feces from public squares in Mar del Plata city, Argentina, and to evaluate the climatic conditions that promote the development of parasites and allow the transmission to people. The study was performed in 21 squares from June 2001 to May 2002. Samples were processed by the Willis technique. Differences in prevalence of parasites were examined for significance by the Chisquare test. Climatic data were obtained from the Library of the National Meteorological Service of Argentina. Total parasitic prevalence was higher in winter than in summer. The prevalence of Ancylostoma spp. was higher in the summer-autumn period. For Toxocara canis, the prevalence was higher in winter whereas for Trichuris vulpis, it was higher in winter, spring and summer. This work shows high prevalence of total parasites throughout the year. For Ancylostoma spp., summer and autumn might be the seasons with higher sanitary risk. On the other hand, T. canis could present the higher risk to people in winter and, T. vulpis, would be transmitted throughout the whole year. The seasonal variation in prevalence of dog parasites results in continuous exposure to people visiting the squares, not only Mar del Plata residents but also tourists from other regions of Argentina and the world, with at least one species of parasite with sanitary risk.

El objetivo de este trabajo es analizar la variación estacional de la prevalencia de los parásitos presentes en las heces caninas halladas en plazas públicas de la ciudad de Mar del Plata y evaluar aquellas condiciones climáticas que promueven su desarrollo y permiten su transmisión a la gente. El estudio se realizó en 21 plazas desde junio de 2001 hasta mayo de 2002. Las muestras fueron procesadas con la técnica de Willis. Se utilizó el test de c² para comparar la prevalencia de los diferentes parásitos. Los datos climáticos fueron obtenidos en la biblioteca del Servicio Meteorológico Nacional. La prevalencia total de parásitos fue considerablemente más alta en invierno que en verano. Ancylostoma spp. fue la especie prevalente en el período otoño-verano. La incidencia de Toxocara canis fue más alta en invierno que en el resto de las estaciones, y la de Trichuris vulpis fue alta en invierno, primavera y verano. Este trabajo muestra alta prevalencia de parásitos totales a lo largo de todo el año en las plazas públicas de Mar del Plata. Para Ancylostoma spp. verano y otoño podrían ser las estaciones con riesgo sanitario más alto para la gente. Por otra parte, T. canis podría presentar mayor riesgo para la gente en invierno y T. vulpis sería transmitido durante todo el año. La variación estacional en la prevalencia de los distintos parásitos caninos, con al menos una especie con riesgo sanitario, hace que la exposición para la gente que visita las plazas sea continua e involucre no sólo a la gente que vive en Mar del Plata sino también turistas de otras regiones de Argentina y el mundo.

Influence of Climate Factors and PM10 on Rotaviral Infection: A Seasonal Variation Study / 대한소아소화기영양학회지

PURPOSE: Recently, while the authors were experiencing that the epidemic period of rotaviral infection happened more in the early spring, we tried to find out how the outbreaks of rotaviral infection are changing in detail depending on the weather condition since it has something to do with the climate factors and PM10. METHODS: Fourteen hundreds seventy nine patients who were proved to be positive to rotavirus were chosen among children less than 5 years old from January 1995 to June 2003. Among various climate factors, monthly average temperature, humidity, rainfall and PM10 were selected. RESULTS: Rotaviral infection was most active in 2002 as 309 (20.9%) patients. It has been the spring that is the most active period of rotaviral infection since 2000. The temperature (RR=0.9423, CI= 0.933424~0.951163), rainfall (RR=1.0024, CI=1.001523~1.003228) and PM10 (RR=1.0123, CI= 1.009385~1.015248) were significantly associated with the monthly distribution of rotaviral infection. CONCLUSION: Through this study we determined that the epidemic period of rotaviral infection is changed to spring, which is different from the usual seasonal periods such as late fall or winter as reported in previous articles. As increased PM10 which could give serious influence to the human body, and changing pattern of climate factors such as monthly average temperature and rainfall have something to do with the rotaviral infection, we suppose that further study concerning this result is required in the aspects of epidemiology, biology and atmospheric science.

The Annual and Seasonal Changes in the Prevalence of Rotaviral Infection from: 1993 to 1998

PURPOSE: Rotavirus infection is a leading cause of severe gastroenteritis among infants and young children worldwide. In temperate regions, institutional outbreaks of the disease occur mainly in cold dry weather, whereas in tropical settings its seasonal course is less well defined. We studied the annual changes in the seasonal prevalence of rotavirus infection for 5 years. METHODS: The study was conducted on 502 patients who lived in Taejon city and its vicinity. They were diagnosed with rotavirus gastroenteritis by stool latex coagulation method in Eulji Medical College Hospital from July 1993 to June 1998. RESULTS: During the 5-years period, 502 fecal specimens were positive by rotavirus latex coagulation method. The peak of the infection occurred in 1994 (July 1994-June 1995), 152 cases (30.3%) from July 1994 to June 1995 and the next peak occurred in 111 cases (22.1%) from July 1993 to June 1994. The seasonal peaks of the infection occurred in December 1993 (17.1%) and January 1994 (21.1%) and in March 1996 (23.4%) and March 1997 (22.5%). CONCLUSOIN: We observed that the seasonal peak in rotavirus infection changed over a 5-year period. The timing of rotavirus activity peaked during December-January(1993 and 1994), Februray-March (1996), and March-April (1997).