Transcript Water-borne diseases - 2014 Water and Health Conference

Spatial patterns of water-borne diseases in relation with climatic conditions in Tashkent Province, Uzbekistan
Feruza Alimova and Dilorom Fayzieva (Research Institute of Irrigation and Water Problems, Uzbekistan)
Abstract:
Nowadays impact of climatic conditions on water quality
and human health is very important issue. Climatic changes
over recent decades have probably already affected some
health outcomes. According to the World Health
Organization Report (2002) climate change was estimated
to be responsible in 2000 for approximately 2.4% of
worldwide diarrhoea, and 6% of malaria in some middleincome countries.
An impact of climate change on population health in
Uzbekistan has been done in the Second National
Communication (2008), where consideration was given first
of all to the dynamics of indicators describing and
characterizing thermal and meteotropic diseases, seasonal
infections, malaria as well as certain parasitic diseases. It
was revealed that intestinal infections belong to indirect
climate change after-effects, which can occur through lack
of clean drinking water and food. Living conditions
represent an additional risk factor. Though Water supply
averages 83.8% in Uzbekistan, with 78.5% for rural areas.
Rural population usually uses open sources such as ‘aryks’,
water reservoirs, rivers and channels for potable. Water
Figure 1: Location of Tashkent Province
quality of these sources significantly deteriorated especially
in the downstream areas of the river basins. Periodic
droughts causing deterioration of sanitary and
epidemiological situation are additional risk factor. Under
hot climate conditions hygienic norm of water consumption
increases, and toxic effect of harmful substances contained
in drinking water grows along with epidemiological role of
water sources with low quality water. Due to climate
warming this trend will progress.
The findings of the study in selected areas of Tashkent
Province show high level of correlation between air
temperature and acute intestinal infections, including
bacterial dysentery. It explains seasonal increasing of this
group of diseases in studied territory.
Findings of the study carried out in Tashkent Province show
that bacterial parameters of water have no associations
with precipitation due to absence of heavy rainfall and Figure 2: Average rate of water-borne diseases in districts and towns of
Tashkent Province for the five years period from 2006 to 2010.
flooding in selected territories.
Background:
Methods:
Climate change has direct influence on the development of various pathogens, including causative
agents of acute intestinal diseases. This influence was described in several publications (e.g.
Campbell-Lendrum et al., 2003). The level of temperature sensitivity observed in Uzbekistan is
consistent with, but somewhat higher than that observed in similar studies in other regions
(Checkley et al., 2000; Singh et al., 2001). With the increase in temperatures and relative humidity
Uzbekistan faces the risk of increasing microbial and protozoan pathogen replication rates as well
as, possibly better survival of enteric viruses in the natural environment. Climate change is adversely
affecting the health of populations around the world, with the greatest impacts in low-income
countries (Confalonieri et al., 2007; McMichael et al., 2003a; WHO, 2002; WHO, 2009). The first
detectable changes in human health may well be alterations in the geographic range (latitude and
altitude) and seasonality of certain infectious diseases – including vector-borne infections such as
malaria and dengue fever, and water and food-borne infections (e.g. acute intestinal infections,
salmonellosis) which peak in the warmer months. Warmer average temperatures combined with
increased climatic variability would alter the pattern of exposure to thermal extremes and the
resultant health impacts, in both summer and winter.
Climate data Monthly precipitation and temperature data
Figure 3: Correlation between
Coli-index and air temperature
Figure 5: Correlation between
Coli-index and precipitation
Figure 4: Correlation between
Total Microbial Count (TMC) and
air temperature
Figure 6: Correlation between
Total Microbial Counts (TMC) and precipitation
y = 0,009x2 - 0,0275x + 0,7531
R² = 0,9755
7
Results:The figure 3 shows direct correlation between Coli- index and
6
-5
12
5
10
4
8
3
2
6
4
1
2
0
0
0
5
10
15
20
25
30
y = 0.014x2 + 0.019x + 1.199
R² = 0.864
14
Morbidity
Morbidity
air temperature in Yangiyul, Parkent, Urtachirchik districts and Angren
town. High correlation
(between 0.801 and 0.9) has been revealed
in the three analysed district and one town analysed. It proves
oursuggests that assumption that air temperature has influence on
growth of coliform bacterias in water is correct. The figure 4 describes
correlation between TMC and air temperature in studied districts. High
correlation between analyzing factors presented in this map. Direct
correlation in Yangiyul district (0.601-0.7) higher than in other studied
districts (0.501-0.6) was revealed. These results show point to
substantial influence of air temperature to the microbial water quality.
The figure 5 illustrates correlation between coli-index and precipitation
in studied districts. An inverse correlation between analyzed factors
means that in the result of intensive precipitation decreasing the value
of coli-index in water. The low correlation has been revealed in
Yangiyul, Urtachirchik districts and Angren town (-0.465 and -0.419)
than in Parkent district (between -0.232 and 0.286). The figure 6 shows
inverse correlation between TMC and precipitation in studied three
districts and one town. The lower level of inverse correlation has been
revealed in Parkent district (-0.364 and -0.328), than in other studied
areas. The revealed difference is insignificant.
The figure 7 illustrates correlation between three integrated factors:
climate, water quality and acute intestinal infections diseases. As figure
shows, there is high correlation between climate, water quality, and AII
observed in Yangiyul district (0.801 -0.9). There was lower correlation
between these three factors in other districts selected for study
(among 0.101 and 0.200). The figure 8 shows low level of correlation
between climate, water quality and Bacterial Dysentery (0.101 and
0.2).
for five years (2006-2010) have been obtained from the
Agency of Hydrometeorology of the Cabinet Ministers of
the Republic of Uzbekistan (Uzhydromet). There are 35
hydro-meteorological posts in Tashkent Region, including
14 which monitor daily meteorology data.
Water quality Monthly data on bacteriological indicators
of water quality as Total Microbial Counts and Coli-index
data in 5 towns and 15 districts of Tashkent Region was
obtained from the Regional Centre of Sanitary
Epidemiological Surveillance of (TashOblCSES) of the
Ministry of Health of the Republic of Uzbekistan for the
period of five years (2006-2010).
Health data Monthly data for two types of water-borne
diseases (acute intestinal infections and bacterial
dysentery) in 5 towns and 15 districts were obtained from
the Ministry of Health of the Republic of Uzbekistan for
the period of five years (2006-2010).
Overall data has been transformed into GIS (spatial).
The formed database was processed statistically for carry
out correlation analyses between climate conditions,
water quality and diseases.
-5
0
5
10
15
20
25
30
Temperature
Temperature
Figure 9.: Correlation of AII incidence
and mean monthly air temperature for 5 years
Figure 10: Correlation of Bacterial Dysentery incidence
and mean monthly air temperature for 5 years
Conclusions:
•Analyzing of data on climate, water quality and
water-borne diseases in the studied districts give
grounds to assume that the rates of the above
diseases are significantly contributed by microbial
growth in potable water under the impact of air
temperature.
•Despite various opinions about the negative impact
of polluted water sources aggravated by hot climate
on the health of the population the necessity of
further extensive research is dictated by insufficiently
revealed cause-and-effect relationship in this field.
Figure 7: Correlation between
climate, water quality and Acute
Intestinal Infections
Figure 8: Correlation between
climate, water quality and Bacterial
Dysentery
The rates of acute intestinal infections given for the period of 2006-2010, high rate
of disease was revealed in Yangiyul, Akkurgan, Toshkent and Kuyichirchik districts in
2006. More cases were registered in Urtachirchik and Akkurgan districts in 2007.
High rates of acute intestinal infections were revealed in Yangiyul district in 2008,
2009 and 2010. Based on the results of the study, it can be concluded that Yangiyul
district is the most vulnerable area regarding the incidence of acute intestinal
infections. It can be explained, that geographically Yangiyul district is located in
downstream area of the Chirchik River basin. This district accepts urban sewerage
waters from Tashkent city discharged to the canal Salar after biological treatment.
The efficiency of abovementioned treatment plant equals to 55-65%, due to old
facility constructed at the beginning of 70s of the last century.
The findings of the study in selected areas of Tashkent Province
show high level of correlation between air temperature and
acute intestinal infections, including bacterial dysentery. It
explains seasonal increasing of this group of diseases in studied
territory.
References:
Campbell-Lendrum, Wilkinson, P., D.H. and Bartlett, C.L., 2003.
Monitoring the health effects of climate change. In: A. McMichael
et al. (Editors), Climate Change and Human Health: Risks and
Responses. World Health Organization, Geneva, pp. 322.
WHO, (2000).
•The findings of the study in selected areas of
Tashkent Province show high level of correlation
between air temperature and acute intestinal
infections, including bacterial dysentery. It explains
seasonal increasing of this group of diseases in studied
territory.
•Findings of the study carried out in Tashkent Province
show that bacterial parameters of water have no
associations with precipitation due to absence of
heavy rainfall and flooding in selected territories.
•The strong correlation (R²= 0, 801) was revealed
between climate, water quality and Acute Intestinal
Infections in Yangiyul district of Tashkent region.