Spatial Clustering and Epidemiological Aspects of Visceral Leishmaniasis in Two Endemic Villages, Baringo District, Kenya

Ryan, Jeffrey R.; Mbui, Jane; Rashid, Juma; Wasunna, Monique; Kirigi, George; Magiri, Charles; Kinoti, Dedan; Ngumbi, P. M.; Martin, Samuel K.; Odera, Shadrak O.; Hochberg, Lisa P.; Bautista, Christian T.; Chan, Adeline

doi:10.4269/ajtmh.2006.74.308

Cited by 49 publications

(36 citation statements)

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“…Generally, poor housing construction was found to be characteristics of the study area where visceral leishmaniasis was prevalent and vector density is also high. The reports of earlier workers, also support these findings and have been reported that mud plastered household and cattle shed are suitable for the development of phlebotomine species in Indian sub-continent [16,17], Brazil[18] and Kenya [19] respectively. The largest odds ratios, however, are associated with wall types of the houses.…”

Section: Discussionsupporting

confidence: 73%

Study of house-level risk factors associated in the transmission of Indian Kala-azar

et al. 2010

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BackgroundIn visceral leishmaniasis (VL), phlebotomine vectors are the main target to reduce for control measures. An attempt has been taken to delineate the association between Phlebotomous argentipes and housing characteristics between two districts e.g. endemic and non-endemic.MethodsA cross-sectional survey was conducted on 240 households for both the endemic (Vaishali district) and non-endemic (Lohardaga district) site. Logistic regression analysis was used to identify factors related to housing characteristics influencing suitable habitats for P. argentipes. Vector density estimated using a CDC light trap.ResultsThe proportion of P. argentipes in both endemic and non-endemic areas was significantly much higher (P < 0.001) when compared with the proportion of Sergentomiya and P. papatasi. The results of multilevel logistic regression analysis showed that mud plastered wall (P value = 0.001), mixed dwelling (P value = 0.002) and area (P value = 0.001) were strongly associated with the presence of vectors.ConclusionResult of the studied household characteristics provides an accurate, rapid assessment of house-level variation in risk. The results also have implications for maximizing surveillance efficacy of sandflies, which is likely to become increasingly important while formulating any control strategy.

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Section: Discussionsupporting

confidence: 73%

Study of house-level risk factors associated in the transmission of Indian Kala-azar

et al. 2010

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“…Although this may work well on maps that show relatively large geographical units (such as those used in the present study), it may not work as well on a smaller scale, where neighbourhood-level geographical barriers, such as rivers or train tracks, could create non-circular interaction patterns. However, the Spatial Scan Statistics employed in the present study has higher statistical power than other geostatistical methods and has been widely applied to the detection of clustering of diseases [18-21]. …”

Section: Discussionmentioning

confidence: 99%

Targeting the hotspots: investigating spatial and demographic variations in HIV infection in small communities in South Africa

Wand

Ramjee

2010

Journal of the International AIDS Society

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BackgroundIn South Africa, the severity of the HIV/AIDS epidemic varies according to geographical location; hence, localized monitoring of the epidemic would enable more effective prevention strategies. Our objectives were to assess the core areas of HIV infection in KwaZulu-Natal, South Africa, using epidemiological data among sexually active women from localized communities.MethodsA total of 5753 women from urban, peri-rural and rural communities in KwaZulu-Natal were screened from 2002 to 2005. Each participant was geocoded using a global information system, based on residence at time of screening. The Spatial Scan Statistics programme was used to identify areas with disproportionate excesses in HIV prevalence and incidence.ResultsThis study identified three hotspots with excessively high HIV prevalence rates of 56%, 51% and 39%. A total of 458 sexually active women (19% of all cases) were included in these hotspots, and had been exclusively recruited by the Botha's Hill (west of Durban) and Umkomaas (south of Durban) clinic sites. Most of these women were Christian and Zulu-speaking. They were also less likely to be married than women outside these areas (12% vs. 16%, p = 0.001) and more likely to have sex more than three times a week (27% vs. 20%, p < 0.001) and to have had more than three sexual partners (55% vs. 45%, p < 0.001). Diagnosis of genital herpes simplex virus type 2 was also more common in the hotspots. This study also identified areas of high HIV incidence, which were broadly consistent with those with high prevalence rates.ConclusionsGeographic excesses of HIV infections at rates among the highest in the world were detected in certain rural communities of Durban, South Africa. The results reinforce the inference that risk of HIV infection is associated with definable geographical areas. Localized monitoring of the epidemic is therefore essential for more effective prevention strategies - and particularly urgent in a region such as KwaZulu-Natal, where the epidemic is particularly rampant.

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“…Such differences might reflect not only variations in the magnitude of transmission between these areas but also differences in the diagnostic methods used and the age distribution within the studied population. Ryan et al (2006), while studying two villages in Kenya, found a linear relationship between seroprevalence for VL and age. Because our study included all age groups this feature could be an explanation for the high prevalence reported here.…”

Section: Discussionmentioning

confidence: 99%

Leishmania infection in humans, dogs and sandflies in a visceral leishmaniasis endemic area in Maranhão, Brazil

Felipe

Aquino

Kuppinger

et al. 2011

Mem. Inst. Oswaldo Cruz

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Visceral leishmaniasis (VL) is considered an important neglected disease that affects many countries of the world (Desjeux 2004). On the American continent, VL is caused by the protozoan parasite Leishmania chagasi, which is transmitted to humans and other vertebrate hosts (e.g., dogs) through the bite of a female sandfly. Lutzomyia longipalpis is considered to be the main vector for VL in Brazil (Lainson & Rangel 2005).A high proportion of L. chagasi infected persons do not present any clinical symptoms of disease, even after a long incubation period (asymptomatic form) (Evans et al. 1992, Romero et al. 2009). Cohort studies in Brazil have described detection of asymptomatic seroconvertors with a sensitive and specific enzyme linked immunosorbent assay (ELISA) test using crude antigens from promastigotes (Badaró et al. 1986a, c) Malnutrition is considered one of the most important factors associated with the development of clinical symptoms of leishmaniasis (Alvar et al. 2006). The high frequency of Leishmania infection found in human beings, dogs and Lu. longipalpis in previous studies in the municipality of Raposa, state of Maranhão (MA), Brazil, may also be associated with poverty (Caldas et al. 2001(Caldas et al. , 2002.Notably, the current knowledge on the epidemiology of VL is mainly based on studies examining the prevalence of Leishmania infections only among humans. There are few studies that simultaneously examine L. chagasi infection across several known hosts and carriers. Therefore, the aim of the present study was to determine the asymptomatic L. chagasi infection rates in human beings, dogs and the vector Lu. longipalpis in the VL endemic area of Raposa. PATIENTS, MATERIALS AND METHODSThe study was performed from August 2006-July 2008 in Vila Maresia, Vila Marisol and Vila Pantoja; all three neighbourhoods are located in the municipality of Raposa situated in the northern coastal region of MA, approximately 28 km from the state capital, São Luis (Figure).In this study, the inclusion criteria for human subjects were the following: living in an endemic area for more than six months, no signs and symptoms of VL (fever for more than 2 weeks, hepatosplenomegaly, weight loss or mucocutaneous pallor) and no previous history of VL. As exclusion criteria, we considered a history of treatment for VL (including treatment failures and relapses), individuals with known immunodeficiency or currently using immunosuppressants and comorbidities (evidence of other conditions leading to splenomegaly, such as schistosomiasis and malaria).In a preliminary census survey, we found 1,417 inhabitants, 986 (70%) of whom participated in the study. This 30% loss was mainly due to internal and external migrations, as well as refusal to participate in the study. Overall, 986 (69.6%) out of 1,417 inhabitants that lived more than six months in the area and did not exhibit clinical VL symptoms participated in the study. From these, 857 individuals (86.9%) were from Vila Maresia, 77 individuals (7.7%) were from Vila Marisol and 52...

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Spatial Clustering and Epidemiological Aspects of Visceral Leishmaniasis in Two Endemic Villages, Baringo District, Kenya

Cited by 49 publications

References 41 publications

Study of house-level risk factors associated in the transmission of Indian Kala-azar

Study of house-level risk factors associated in the transmission of Indian Kala-azar

Targeting the hotspots: investigating spatial and demographic variations in HIV infection in small communities in South Africa

Leishmania infection in humans, dogs and sandflies in a visceral leishmaniasis endemic area in Maranhão, Brazil

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