Hatha, A A M; Abhirosh, Chandran; Sherin, Varghese; Ellen, Kandeler; Ambattu, Thomas; Asit, Mazumder(Elsevier, January 15, 2011)
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Abstract:
Microcosm studies were performed to evaluate the survival of Escherichia coli, Salmonella paratyphi and
Vibrio parahaemolyticus in water and sediment collected from the freshwater region of Vembanad Lake
(9 35◦N 76 25◦E) along the south west coast of India. All three test microorganisms showed significantly
(p < 0.01) higher survival in sediment compared to overlying water. The survival in different sediment
types with different particle size and organic carbon content revealed that sediment with small particle
size and high organic carbon content could enhance their extended survival (p < 0.05). The results indicate
that sediments of the Lake could act as a reservoir of pathogenic bacteria and exhibit a potential health
hazard from possible resuspension and subsequent ingestion during recreational activities. Therefore,
the assessment of bacterial concentration in freshwater Lake sediments used for contact and non contact
recreation has of considerable significance for the proper assessment of microbial pollution of the
overlying water, and for the management and protection of related health risk at specific recreational
sites. Besides, assessment of the bacterial concentration in sediments can be used as a relatively stable
indicator of long term mean bacterial concentration in the water column above
Description:
International Journal of Hygiene and Environmental Health 214 (2011) 258– 264
Hatha, A A M; Abhirosh, Chandran; Sherin, Varghese(I W A Publishing, 2008)
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Abstract:
Prevalence of faecal indicator bacteria, Escherichia coli and pathogenic bacteria, Vibrio cholerae,
Vibrio parahaemolyticus and Salmonella were analysed in Vembanadu lake (98350N 768250E), along
south west coast of India for a period of one year from ten stations on the southern and northern
sides of a salt water regulator constructed in Vembanadu Lake in order to prevent incursion of
seawater during certain periods of the year. While the northern side of the lake has a connection
to the sea, the southern side is enclosed when the salt water regulator is closed. The results
revealed the water body is polluted with high faecal coliform bacteria with mean MPN value
ranging from 1718-7706/100 ml. E. coli, V. cholerae, V. parahaemolyticus and Salmonella
serotypes such as S. paratyphi A, B, C and S. newport were isolated and this is the first report on
the isolation of these Salmonella serovars from this lake. E. coli showed highest percentage of
incidence (85.6–86.7%) followed by Salmonella (42–57%), V. choleare (40–45%) and V.
parahaemolyticus (31.5–32%). The increased prevalence of indicator and pathogenic bacteria in
the enclosed southern part of Vembanadu Lake may be resulting from the altered flow patterns
due to the salt water regulator.
Hatha, A A M; Chandran, Abhirosh; Asit, Mazumder; Sherin, Varghese; Thomas, A P(Cochin University of Science and Technology, 2013)
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Abstract:
Contamination of environmental water by pathogenic microorganisms and subsequent
infections originated from such sources during different contact and non- contact
recreational activities are a major public health problem worldwide particularly in
developing countries. The main pathogen frequently associated with enteric infection in
developing countries are Salmonella enterica serovar typhi and paratyphi. Although the
natural habitat of Salmonella is the gastrointestinal tract of animals, it find its way into
natural water through faecal contamination and are frequently identified from various
aquatic environments (Baudart et al., 2000; Dionisio et al., 2000; Martinez -Urtaza et al., 2004.,
Abhirosh et al., 2008). Typhoid fever caused by S. enterica serotype typhi and paratyphi are a
common infectious disease occurring in all the parts of the world with its highest
endemicity in certain parts of Asia, Africa, Latin America and in the Indian subcontinent
with an estimated incidence of 33 million cases each year with significant morbidity and
mortality (Threlfall, 2002). In most cases the disease is transmitted by polluted water (Girard
et al., 2006) because of the poor hygienic conditions, inadequate clean water supplies and
sewage treatment facilities. However in developed countries the disease is mainly associated
with food (Bell et al., 2002) especially shellfish (Heinitz et al., 2000
Hatha, A A M; Abhirosh, C; Sherin, V; Thomas, A P; Abhilash, P C(Springer India, August 3, 2010)
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Abstract:
Prevalence of faecal coliform bacteria and the
survival of Escherichia coli, Vibrio parahaemolyticus and
Salmonella paratyphi were studied in the water and sediment
from Vembanadu Lake in the presence and absence
of protozoan predators. The density of faecal coliform bacteria
ranged between mean MPN value 5080–9000/100 ml
in water and 110,000–988,000/1 g in sediment (p <0.01),
which was 110 times greater than in overlying water. The
laboratory microcosm studies revealed that E. coli, V. parahaemolyticus
and S. paratyphi showed significantly higher
survival (p <0.05) potential in sediment than in overlying
water both in the presence and absence of protozoan predators.
The results indicate that Vembanadu Lake sediment
constitutes a reservoir of pathogenic bacteria and exhibits
potential health hazard from possible resuspension and subsequent
ingestion during recreational activities. Therefore,
assessment of bacterial concentration in freshwater lake sediments
used for contact and non-contact recreation is of considerable
significance for the proper assessment of microbial pollution of the overlying water and the management
and protection of related health risk at specific recreational
sites. In addition, assessment of the bacterial concentration
in sediments can be used as a relatively stable indicator of
long-term mean bacterial concentration in the water column
above.