Variability Modeling of Rainfall, Deforestation, and Incidence of American Tegumentary Leishmaniasis in Orán, Argentina, 1985–2007

Abstract

American tegumentary leishmaniasis (ATL) is a disease transmitted to humans by the female sandflies of the genus Lutzomyia. Several factors are involved in the disease transmission cycle. In this work only rainfall and deforestation were considered to assess the variability in the incidence of ATL. In order to reach this goal, monthly recorded data of the incidence of ATL in Orán, Salta, Argentina, were used, in the period 1985–2007. The square root of the relative incidence of ATL and the corresponding variance were formulated as time series, and these data were smoothed by moving averages of 12 and 24 months, respectively. The same procedure was applied to the rainfall data. Typical months, which are April, August, and December, were found and allowed us to describe the dynamical behavior of ATL outbreaks. These results were tested at 95% confidence level. We concluded that the variability of rainfall would not be enough to justify the epidemic outbreaks of ATL in the period 1997–2000, but it consistently explains the situation observed in the years 2002 and 2004. Deforestation activities occurred in this region could explain epidemic peaks observed in both years and also during the entire time of observation except in 2005–2007.

The role of deforestation on American cutaneous leishmaniasis incidence: spatial‐temporal distribution, environmental and socioeconomic factors associated in the Brazilian Amazon

“…Continuous deforestation tends to increase the distance between families and forest (vector habitat and parasite cycle), reducing the contact between man and vectors. Contrastingly, it is likely that areas of recent deforestation may also contribute to the transmission of ACL, since deforestation is mainly caused by disordered occupation, road construction, agriculture, and livestock activities, placing individuals in close proximity to the vector .…”

Monte Carlo simulation of American Tegumentary Leishmaniasis epidemic. The case in Oran, Salta, Argentina, 1985-2007

“…Chaves & Pascual (2006) [6] by analyzing the boxplot with monthly square-root transformed CL cases in Costa Rica presented, in average, a seasonal peak during May, though epidemic outbreaks happened around the year, as demonstrated by the existence of outliers in February, July, September, October, November, and December. In contrast to the issue raised by Chaves & Pascual (2006) [6], the simulations obtained here, using the time series data from the region of Department of Orán, can be grouped by months and evaluate the respective boxplot, and we found that outbreaks occurred in April, September and December with a standard deviation of one month, for more details see Rosales et al (2014) [19]. The empirical cumulative distribution functions (CDF) obtained from simulations, exemplified in Figure 5, allow to notice where the setting is more suitable for real human cases (red line).…”

Spatial–temporal pattern of cutaneous leishmaniasis in Brazil

“…These environmental variables are typical of the Legal Amazon region in which we detected the most likely cluster of CL. Other studies have also shown positive association of CL cases and human environmental changes such as deforestation [ 37 ], settlements near forested areas [ 32 , 38 ] and development of agriculture crops [ 39 , 40 ]. These activities are predominant at the border of the Legal Amazon in a location called “Arc of Deforestation” [ 41 ], where we found most of the CL hotspots.…”