Role of remote sensing, geographical information system (GIS) and bioinformatics in kala-azar epidemiology

Landscape effects on the abundance of Lutzomyia longipalpis and Migonemyia migonei (Diptera: Psychodidae: Phlebotominae) in Corrientes city, northern Argentina

We analyses the relationship between landscape and environmental variables estimated from high-resolution satellite images with the temporal variation of the abundance of Lutzomyia longipalpis and Migonemyia migonei, vectors of leishmaniasis, in Corrientes city. At 8 collection sites, 14 samples were conducted between March 2012 to February 2014. Proportion of land cover classes derived from high resolution satellite images as: water, bare soil, urban areas, low vegetation and high vegetation, as well as average, maximum and minimum values of Normalized Difference Vegetation Index and Normalized Difference Water Index) in buffer areas of 50 m, 100 m and 150 m were used to characterize and identify suitable environmental conditions for the development of sand flies through Generalized Linear Mixed Models. The most frequently collected species during the sampling period was Lu. longipalpis and followed by Mg. migonei. The models showed that high Lu. longipalpis abundance were related to low proportion of high vegetation coverage, while a negative association was among Mg. migonei abundance and with values of Normalized Difference Water Index and with the interaction between urban areas and minimum values of Normalized Difference Water Index, and a positive association with the interaction between low vegetation and average values of Normalized Difference Water Index.

Uso e cobertura do solo e prevalência de leishmaniose visceral canina em Teresina, Piauí, Brasil: uma abordagem utilizando sensoriamento remoto orbital

Resumo: Este estudo examina a associação entre uso e cobertura do solo e a ocorrência de leishmaniose visceral (LV) canina. Estudo caso-controle em que casos foram residências com cães soropositivos para LV canina e controles, as residências com cães soronegativos. Utilizaram-se imagens de sensoriamento remoto (CBERS: 2/CCD e 2B/HRC) para descrever o uso e cobertura do solo em quadrículas de 625m2 na região do estudo. A chance da LV canina foi duas vezes maior em domicílios localizados em quadrículas com área ≤ 25m2 coberta por estruturas residenciais com pouca vegetação em comparação com aquelas em que essa cobertura alcançou ≥ 600m2. Domicílios localizados em quadrículas com até metade da área coberta por estruturas residenciais com muita vegetação tiveram chances 65% menores de LV canina em comparação com aquelas situadas em áreas quase totalmente cobertas por essa característica. Como a infecção canina costuma preceder a ocorrência de casos humanos, a identificação de características de uso e cobertura do solo associadas à LV canina pode contribuir para a delimitação de áreas de risco para LV humana.

Remote sensing and disease control in China: past, present and future

Satellite measurements have distinct advantages over conventional ground measurements because they can collect the information repeatedly and automatically. Since 1970 globally and 1985 in China, the availability of remote sensing (RS) techniques has steadily grown and they are becoming increasingly important to improve our understanding of human health. This paper gives the first detailed overview on the developments of RS applications for disease control in China. The problems, challenges and future directions are also discussed with an aim of guiding prospective studies.

Measles laboratory-based surveillance in Zimbabwe during 2004-2009

INTRODUCTION

Zimbabwe has for a long time satisfied measles elimination criteria according to the World Health Organization Regional Office for Africa (WHO/AFRO) measles surveillance standards. In this elimination phase laboratory based surveillance becomes critical as it gives evidence on the interruption of transmission of measles virus in the country hence the performance of the laboratory has to be monitored.

METHODS

This retrospective study assesses measles laboratory performance in Zimbabwe from 2004 to 2009 by monitoring laboratory surveillance quality indicators against predefined WHO indicators.

RESULTS

Overall, 92.20% of serum specimens arrived in the laboratory in good condition, 66.8% were received in the lab within the stipulated three days and 77% of the results were sent back to the national centers within 7 days. The laboratory passed all external proficiency tests from 2005 to 2009 with 100%. The laboratory sent 13.42% of representative sera for regional reference laboratory co-testing and the concordance of results was 98.33%. An average of 27.33% of patients with positive measles IgM had vaccination history.

DISCUSSION

Available data shows that four out of the six WHO surveillance indicators were met by the national laboratory. The timeliness of specimen shipment to the lab needs to be improved and results should be communicated to the national centers in a timely manner. Cases with no vaccination history may be due to incompletely filled out forms or inadequate case investigation. Unvaccinated cases can accumulate over time and cause outbreaks.

CONCLUSION

The results of the external proficiency tests show that the laboratory is performing well, with adherence to quality requirements, as indicated by proficiency tests with the regional reference laboratory. Hence the results generated by the laboratory may be reliable for surveillance.