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Diagnostic approach for monitoring hydroclimatic conditions related to emergence of west nile virus in west virginia.

Jutla A, Huq A, Colwell RR - Front Public Health (2015)

Bottom Line: Analysis of land surface temperature (LST) pattern shows that temperature values >16°C, with heavy precipitation, may lead to abundance of the mosquito population.This hypothesis was tested in West Virginia where a sudden epidemic of WNV infection was reported in 2012.Our results emphasize the value of hydroclimatic processes estimated by satellite remote sensing, as well as continued environmental surveillance of mosquitoes, because when a vector-borne infection like WNV is discovered in contiguous regions, the risk of spread of WNV mosquitoes increase at points where appropriate hydroclimatic processes intersect with the vector niche.

View Article: PubMed Central - PubMed

Affiliation: Department of Civil and Environmental Engineering, West Virginia University , Morgantown, WV , USA.

ABSTRACT
West Nile virus (WNV), mosquito-borne and water-based disease, is increasingly a global threat to public health. Since its appearance in the northeastern United States in 1999, WNV has since been reported in several states in the continental United States. The objective of this study is to highlight role of hydroclimatic processes estimated through satellite sensors in capturing conditions for emergence of the vectors in historically disease free regions. We tested the hypothesis that an increase in surface temperature, in combination with intensification of vegetation, and enhanced precipitation, lead to conditions favorable for vector (mosquito) growth. Analysis of land surface temperature (LST) pattern shows that temperature values >16°C, with heavy precipitation, may lead to abundance of the mosquito population. This hypothesis was tested in West Virginia where a sudden epidemic of WNV infection was reported in 2012. Our results emphasize the value of hydroclimatic processes estimated by satellite remote sensing, as well as continued environmental surveillance of mosquitoes, because when a vector-borne infection like WNV is discovered in contiguous regions, the risk of spread of WNV mosquitoes increase at points where appropriate hydroclimatic processes intersect with the vector niche.

No MeSH data available.


Related in: MedlinePlus

Percentage change in LST in July 2012 with respect to July 2011. The inset numbers on map are the percent difference in WNV positive mosquitoes during 2012 in counties of West Virginia compared to 2011. (Black box in the figure – 38.6825°N to 37.8788°N; 82.5844°W to 81.0955°; and include Cabell and Kanawha counties of West Virginia).
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Figure 3: Percentage change in LST in July 2012 with respect to July 2011. The inset numbers on map are the percent difference in WNV positive mosquitoes during 2012 in counties of West Virginia compared to 2011. (Black box in the figure – 38.6825°N to 37.8788°N; 82.5844°W to 81.0955°; and include Cabell and Kanawha counties of West Virginia).

Mentions: The 8-day composite LST from MODIS Terra platform was used instead of daily LST data to minimize missing values caused by cloud contamination. Figures 2A,B show eight panels for LST for June and July, respectively. In 2012, Cabell and Kanawha counties showed highest number of WNV positive mosquitoes (Figure 1B). If presence of mosquitoes were related to temperature, a steady increase in temperature should be observed and those regions of high temperatures show more WNV positive mosquitoes. Figure 2A (top left panel) shows distribution of LST (average areal temperature 10.5°C) during the first week of June, 2012. As land surface and air warm, the areal average increased (to 16.0°C) at the end of the fourth week of June. The temperature peaked during the first week of July to 17.5°C, falling sharply thereafter. Traditional time-series based correlation will not be applicable due to limited disease data as well as presence of zeroes in the time series. Two observations from Figure 2 include (i) the largest number of WNV positive mosquitoes were found in regions where a rapid increase in LST occurred (black box in the figure – 38.6825°N to 37.8788°N; 82.5844°W to 81.0955°W; and include Cabell and Kanawha counties of West Virginia) and (ii) the LST dropped within a few weeks in July, with spread of WNV positive mosquitoes limited to western counties of the region (Figure 2B). If the relationship between LST and warm air is valid, then a difference in inter-annual variability of LST should have been observed. Percent difference is shown in Figure 3, between monthly LST in July 2012 (highest number of WNV positive mosquitoes) and July 2011 (relative low number of WNV positive mosquitoes). Western counties (including Cabell and Kanawha, close to the Ohio and Elk rivers, respectively) experienced 10–15% increase in LST in July of 2012, providing complementary evidence that LST is an important hydroclimatic process related to emergence and spread of WNV positive mosquitoes. One may argue that the northeastern counties experienced a similar increase in temperature during 2012 without concurrent increase in the number of WNV positive mosquitoes. However, the maximum temperature recorded in the northeastern counties, which are at higher elevation than the western counties during 2012 was 10°C, compared to 17°C in the western counties (highlighted by the black box), providing a plausible explanation for the absence of mosquitoes in the region and corroborating thresholds for temperature effect on mosquito growth documented by other investigators (13). The counties adjacent to Cabell and Kanawha (e.g., Mason, Putnam, and Lincoln) show similar LST values with Cabell and Kanawha but the number of WNV positive mosquitoes of these counties are very low or 0, this is perhaps lack of environmental sampling in the region. On the other hand, several counties (e.g., Fayette, Nicholas, and Webster) show similar warming trend of LST with Cabell and Kanawha and hence have high number of WNV positive mosquitoes.


Diagnostic approach for monitoring hydroclimatic conditions related to emergence of west nile virus in west virginia.

Jutla A, Huq A, Colwell RR - Front Public Health (2015)

Percentage change in LST in July 2012 with respect to July 2011. The inset numbers on map are the percent difference in WNV positive mosquitoes during 2012 in counties of West Virginia compared to 2011. (Black box in the figure – 38.6825°N to 37.8788°N; 82.5844°W to 81.0955°; and include Cabell and Kanawha counties of West Virginia).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4325936&req=5

Figure 3: Percentage change in LST in July 2012 with respect to July 2011. The inset numbers on map are the percent difference in WNV positive mosquitoes during 2012 in counties of West Virginia compared to 2011. (Black box in the figure – 38.6825°N to 37.8788°N; 82.5844°W to 81.0955°; and include Cabell and Kanawha counties of West Virginia).
Mentions: The 8-day composite LST from MODIS Terra platform was used instead of daily LST data to minimize missing values caused by cloud contamination. Figures 2A,B show eight panels for LST for June and July, respectively. In 2012, Cabell and Kanawha counties showed highest number of WNV positive mosquitoes (Figure 1B). If presence of mosquitoes were related to temperature, a steady increase in temperature should be observed and those regions of high temperatures show more WNV positive mosquitoes. Figure 2A (top left panel) shows distribution of LST (average areal temperature 10.5°C) during the first week of June, 2012. As land surface and air warm, the areal average increased (to 16.0°C) at the end of the fourth week of June. The temperature peaked during the first week of July to 17.5°C, falling sharply thereafter. Traditional time-series based correlation will not be applicable due to limited disease data as well as presence of zeroes in the time series. Two observations from Figure 2 include (i) the largest number of WNV positive mosquitoes were found in regions where a rapid increase in LST occurred (black box in the figure – 38.6825°N to 37.8788°N; 82.5844°W to 81.0955°W; and include Cabell and Kanawha counties of West Virginia) and (ii) the LST dropped within a few weeks in July, with spread of WNV positive mosquitoes limited to western counties of the region (Figure 2B). If the relationship between LST and warm air is valid, then a difference in inter-annual variability of LST should have been observed. Percent difference is shown in Figure 3, between monthly LST in July 2012 (highest number of WNV positive mosquitoes) and July 2011 (relative low number of WNV positive mosquitoes). Western counties (including Cabell and Kanawha, close to the Ohio and Elk rivers, respectively) experienced 10–15% increase in LST in July of 2012, providing complementary evidence that LST is an important hydroclimatic process related to emergence and spread of WNV positive mosquitoes. One may argue that the northeastern counties experienced a similar increase in temperature during 2012 without concurrent increase in the number of WNV positive mosquitoes. However, the maximum temperature recorded in the northeastern counties, which are at higher elevation than the western counties during 2012 was 10°C, compared to 17°C in the western counties (highlighted by the black box), providing a plausible explanation for the absence of mosquitoes in the region and corroborating thresholds for temperature effect on mosquito growth documented by other investigators (13). The counties adjacent to Cabell and Kanawha (e.g., Mason, Putnam, and Lincoln) show similar LST values with Cabell and Kanawha but the number of WNV positive mosquitoes of these counties are very low or 0, this is perhaps lack of environmental sampling in the region. On the other hand, several counties (e.g., Fayette, Nicholas, and Webster) show similar warming trend of LST with Cabell and Kanawha and hence have high number of WNV positive mosquitoes.

Bottom Line: Analysis of land surface temperature (LST) pattern shows that temperature values >16°C, with heavy precipitation, may lead to abundance of the mosquito population.This hypothesis was tested in West Virginia where a sudden epidemic of WNV infection was reported in 2012.Our results emphasize the value of hydroclimatic processes estimated by satellite remote sensing, as well as continued environmental surveillance of mosquitoes, because when a vector-borne infection like WNV is discovered in contiguous regions, the risk of spread of WNV mosquitoes increase at points where appropriate hydroclimatic processes intersect with the vector niche.

View Article: PubMed Central - PubMed

Affiliation: Department of Civil and Environmental Engineering, West Virginia University , Morgantown, WV , USA.

ABSTRACT
West Nile virus (WNV), mosquito-borne and water-based disease, is increasingly a global threat to public health. Since its appearance in the northeastern United States in 1999, WNV has since been reported in several states in the continental United States. The objective of this study is to highlight role of hydroclimatic processes estimated through satellite sensors in capturing conditions for emergence of the vectors in historically disease free regions. We tested the hypothesis that an increase in surface temperature, in combination with intensification of vegetation, and enhanced precipitation, lead to conditions favorable for vector (mosquito) growth. Analysis of land surface temperature (LST) pattern shows that temperature values >16°C, with heavy precipitation, may lead to abundance of the mosquito population. This hypothesis was tested in West Virginia where a sudden epidemic of WNV infection was reported in 2012. Our results emphasize the value of hydroclimatic processes estimated by satellite remote sensing, as well as continued environmental surveillance of mosquitoes, because when a vector-borne infection like WNV is discovered in contiguous regions, the risk of spread of WNV mosquitoes increase at points where appropriate hydroclimatic processes intersect with the vector niche.

No MeSH data available.


Related in: MedlinePlus