WATER-BORNE DISEASES RECORDED IN AND AROUND COURTALLAM

Transcription

1 WATER-BORNE DISEASES RECORDED IN AND AROUND COURTALLAM

2 WATELI-BORNE DISEASE8 RECORDED IN ANDAROUNDCOURTALLAM INTRODUCTION The most common and widespread danger associated with drinking water is contamination either directly or indirectly by sewage, by other wastes or by human or animal excrement. Faecal pollution of drinking water may introduce a variety of intestinal pathogens - bacterial, viral and parasitic. The main bacteria known to occur in contaminated drinking water include strains of Salmonella, Shigella, Escherichia coli, Vibno choleme, Staphylococcus aureus and few others. These organisms may cause diseases that vary in severity from mild gastroenteritis to severe and sometimes fatal dysentely, cholera or typhoid. Potable water used by patients for drinking and bathing, contains excessive number of organisms such as Pseudomonas Flavobacterium, Acinetobacter, Klebsiella and Serratla may produce a variety of infections involving the skin and mucous membranes of the eye, ear, nose and throat. The modes of transmission of bacterial pathogens include ingestion of contaminated water and food, contact with

3 infected persons or animal8 and exposure to aerosols. Although Shigella may be water-borne, water is not the main mute for the spread of Shigellosis but rather person to person contact in crowded living conditions. In conbast, cholera is usually water- borne and Salmonellosis is foodborne. Among the various water-borne pathogens, there exists a wide range of minimum infectious dose levels necessary to cause a human infection. With ingestion of relatively few organisms can cause disease; With Shigella Jexneri, several hundred cells may be needed, whereas many millions of cells of Salmonella serotypes are usually required to cause gastroenteritis. Similarly with toxigenic organisms such as enteropathogenic E.coli and V.cholerae as many as 108 organisms may be necessary to cause illness. The size of the infective dose also varies in different persons with age, nutntional status and general health at the time of exposure (WHO, 1984).

4 Tenkasi is a Municipal town with a population of 1 lakh. The town has a government hospital with the capacity to accommodate about 100 inpatients and facility to treat a minimum of 500 outpatients ~oming from Tenkasi and its environment. The drinking water for these areas comes from Courtallam. In order to portray the water-borne diseases of this study, hospital records available in Tenkasi hospital were searched for a five year period. The search was mainly oriented towards water-borne diseases encountered in the hospital without paying much importance to other cases.

5 Results of water-borne diseases of the hospital records are presented in Fig.14. Since there was no records available about water-borne diseases in the year 1995 and 1996, the records available for the years, 1997, 1998 and 1999 were scrutinized and are presented in Fig.14. Among the various water-borne diseases encountered diarrhoea was the major disease recorded in the hospital. Next to this a good number of typhoid fever were encountered during the same period of study. Among the water-borne diseases recorded, jaundice came in the third place. Minimum number of cholera cases were also recorded during this period.

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7 Contamination by sewage or by human and animal feces is the greatest danger to drinking water supplies. If such contamination is of recent origin and if it has also been due to cases of carriers of enteric diseases, the water may contain the live organisms causing these diseases. The use of such water may result in the occurrence of the respective diseases. Though methods are available for the detection of individual pathogenic organisms, it is neither practicable nor necessary to adopt such tests m routine examination of water supplies. When pathogenic organisms are present, they are almost always out numbered by other faecal organisms and the latter are easier to detect. If they are not found, it can be taken that disease producing organisms are also absent. ACUTE DIARRHOEAL DISEASES Acute diarrhoeal diseases constitute an important cause of morbidity and mortality throughout the world, particularly in infants and children in the developing countries. It has been estimated that some 500 million cases of diarrhoea occur annually among children under five years of age in the developing countries causing 5-18 million deaths. In India, 1.4

8 million children die annually Irom diarrhoeal diseases other than cholera. Apart from causing death due to dehydration, diarrhoeal disease often initiates malnutrition. Diarrhoeal death ranks among the five leading causes of death in young children. Acute diarrhoeal diseases vary in severity from passing inconvenience to a rapidly fatal flux. A large number of microorganisms are known to cause diarrhoea and the causative agents could be identified in only percent of diarrhoeal illness. In the last decade, additional pathogens have been recognized so that now, under optimal laboratory conditions, etiological diagnosis can be established in some 80 percent of cases (Ananthanarayanan and Jayarampaniker, 1990). Escherichta coli E.coli appears to be the most versatile diarrhoeagenic agent. Clinical isolates of E.coli may be conveniently grouped into three categories - opportunistic, enteropathogenic and enterotoxin producing. The opportunistic pathogens are generally harmless in their normal habitat until they gain access to other sites or tissues. Then they cause diseases such as urinary tract infections, septic infections,

9 bactercmia, meningitis, pubonaay infections, abscesses, skin and wound infections. Enteropathogenic E.coli serotypes are distinctly different from opportunistic euotypes and are naturally virulent for humans. The unique capacity to infect is based on their ability to penetrate epithelial cells of the intestinal mucosa and replicate within them. This mechanism of infection gives rise to the dysentery syndrome, abdominal cramps and pus and blood in the stools. The enterotoxin producing E.coli are unable to invade the intestinal mucosa but they release an enterotoxin that is adsorbed in epithelial cell membranes and stimulates adenyl cyclase activity. The increase in cyclic adenosine 3'5' monophosphate (cyclic AMP) leads directly to the increased electrolyte secretion of the gut and cause,diarrhoea syndrome leads to profuse watery discharge from the small intestine not producing histopathologic changes (Pelczar et al., 1985). SALMONELLAE The genus Salmonella includes several species pathogenic to humans and other animals. They can be differentiated from other enteric organisms and within the genus on the basis of biochemical reactions including

10 appear- of colonies on differential media and by serological typing. Some 2000 semtypes of Salmonslla are known, any of which, with the possible exception of Styphi, can cause acute diarrhoea1 disease. But the large majority of outbreaks are caused by S.typhirnuriam, S.enteritidis and about a dozen other serotypes. Typhoid fever is an acute infectious disease caused by Salmonella typhi. Salmonellae invade the ileal epithelial cells and penetrate to the lamina propria and usually initiate bacteremia with fever and other systemic manifestations. The disease is characterized clinically by a continued fever, inflammation of the intestine, formation of intestinal ulcers, enlargement of the spleen, a characteristic rose - spot eruption on the abdomen and toxemia. The usual incubation period is days. Diagnosis may be confirmed by the isolation of causative organisms from blood and stool specimens and by specific agglutination of S.typhi with the patient's blood serum known as the Widal reaction. Paratyphoid fever is a human infectious disease caused by bacterial organisms that are closely related to S.typhi. In general the disease resembles typhoid fever (Jawetz et al., 1980).

11 88IO%x'Lom ShigeUosis is worldwide, being more common in poor, over crowded and unhygienic communities. It has been described as a 'water-washed disease', its incidence decreases as the amount of water used for sanitation increases. All four serotypes of Shigellae produce dysentery. The pathogenesis of dysentery depends on the penetration of epithelial cells of the large bowel and subsequent local multiplication, producing colitis. In addition, shigellae may produce mild watery diarrhoea. The genus Shigella can be differentiated from Salmonella by the fermentation reactions and serological tests. The Shigella do not liquefy gelatin or produce hydrogen sulphide. Several carbohydrates with notable exception of lactose are fermented to produce acid without gas. Humans are the natural reservoir as well as main mode of dissemination. Among four species of Shigella causing dysentery in humans, S.dysenteriae causes the most severe disease because it produces a potent exotoxin.

12 TRICVDBBKHI Vibrio cholem the most spectacular of diarrhoea1 diseases enters the intestines through food or drink. The infective dose is about 108 cells. The site of infection is the small intestine, primarily the jejunum, where it multiplies and elaborates the enterotoxin. They are gram negative curved rods usually motile by means of one to three polar flagella occurring as saprophytes found in water. The type species of this genus is Vibrio cholerae. It is transmitted by contact and water and food contaminated with excreta from patients and convalescent carriers. Cholera caused by Vibrio cholerae runs it course in 2 or 3 days often terminating in death. The symptoms include vomiting and profuse diarrhoea1 (rice water) stools that result in a severe dehydration loss of minerals and increased blood acidity of the body tissues that lead to death. Replacement of fluids, salt, carbonates is essential to treatment. Cholera is a self limiting disease provided the patient does not die from dehydration or shock before recovery. Use of.certain sulfonamides and antibiotics may be helpful in eliminating the vibrios.

13 ST-I These arc spherical gram positive bacteria occuriing in irregular clusters like grapes. S.epidennidis is predominant on human skin. S.aureus is the most pathogenic of staphylococci. Typically it forms golden yellow colonies on nutrient agar and coagulase positive. It hydrolyres substrates such as egg yolk or DNA. The nasal passages provide an especially favourable environment for S.aureus which is often present there in very large numbers. S.aureus often enters the body through a natural opening in the skin barrier, the hair follicles passage through the epidermal layer. Infection of hair follicles occurs as pimples. The enterotoxin produced by S.aureus causes scalded skin syndrome. Some strains of S.aureus produce enterotoxin. When food gets contaminated with such strains, they multiply and elaborate the toxin, which is heat stable. Ingestion of such food results in vomiting and diarrhoea. STREPTOCOCCI Gram positive spherical bacteria grow in chains. Many non-pathogenic streptococci are commonly found inhabiting the mouth,' gastrointestinal tract and upper respiratory system, but some streptococci are responsible for

14 skin idwtions. Thty ~ ~ r eseveral t e toxins and mqmes; among them haemoly6ins which damage red blood cells. The most common species of this group is S.pyogenes causing impetigo of the new born. Sheptocoavtl pharyngifis (Strep throat) is caused by another species. Upper respiratory infection (Scarlet fever) is caused by group A and B haemolytic streptococci. PSEUDOMONADS They are gram negative rods widespread in soil and water. The most prominent species is Pseudomonas aeruginosa which causes outbreaks of Pseudomonas dermatitis. Pseudomonas is often associated with swimming pools and pool type saunas and hot tubs. When a large number of people use these facihties the alkalinity rises and the chlorine becomes less effective, at the same time the concentration of nutrients that support Pseudomonas increases. Competition swimmers are often troubled with Otitis extema or swimmer's ear, a pseudomonad infection of the external ear canal leading to the ear drum. P.aeruginosa produce several exotoxin and an endotoxin. It causes respiratory infections in persons suffering from chronic pulmonary disease especially cystic fibrosis. In

15 bum patients PMudomonas infection produces blue gmn pus caused by the bacterial pigment '~vocvanin'. JAUNDICE Jaundice or hepatitis is an acute infectious disease that affects liver, kidney and spleen. It is caused by five types of viruses such as hepatitis 'A' vi~s (HAV), hepatitis B virus (HAB), non-a hepatitis virus, non-b hepatitis virus and delta hepatitis (Dl virus. Jaundice caused by HAB is a severe disease with a fatality rate as high as 50% as compared to HAV where the fatality rate is only 1%. Entry of HAV is through oral route by contaminated water, food and drink while the other types are through parenteral (injection of infected blood or its products) route. Rarely these viruses may also infect through other means. Incubation time for HAV is days. The virus multiplies in gastrointestinal tract and spreads to the cells of liver, kidney and spleen. Incubation time for HAB is days and at acute stage the liver parenchyma is completely destroyed. For other hepatitis viruses the incubation period varies irom 10 days to 11 weeks.

16 The normal symptoms of jaundice an fever, chills, headache, fatigue, general weakness, nausea, vomiting and dark yellow urine etc. An overview of the water-borne diseases recorded in the Government Hospital, Tenkasi, diarrhoea1 occunences were predominant (Fig.14). However, the hospital records did not reveal the aetiology of the cases. No single organism was pin pointed for the cause of diarrhoea. Hence, various bacterial sources enumerated above might be responsible for this disease. There is a reduction in the number of cases recorded from 1997 to 1999 showing awareness about water-borne diseases among the public and tourists. Next to diarrhoea, typhoid fever was in h~gher number. The blood samples taken from patients were tested for Widal reaction and the cases were confirmed. However, the severity of the disease varied and no mortality was recorded. Jaundice ranked third place among the water-borne diseases recorded. Various causes have been attributed to the cause. The occunences were more in summer than other seasons due to drinking of contaminated water. Most cases confirmed for Hepatitis B virus were fatal.

17 Very few canes of chokra wen recorded and the percentage of occunenct compared to other diseases coming to the hospital was negligible. These casea were treated effectively by parenteral rehydration and antibiotic therapy, therefore no fatality was recorded. Whenever the disease was recorded, immediate and effective sanitary measures were taken by local authorities thereby the disease was brought under control.

18 1. Occurrence of water-borne diseases is very common in India since safe drinking water is not available to all people in the country especially people living in water scarce areas. Hence, safe drinking water must be made available to all people by the respective governments. 2. Among water-borne diseases recorded at Tenkasi government Hospital only four diseases namely diarrhoea, jaundice, typhoid fever and very few cases of cholera were recorded and treated. 3. Proper treatment was given to cases admitted in the government hospital. Those patients who were admitted for jaundice with Viral Hepatitis-B died in the hospital. However, this percentage was negligible compared to other diseases admitted in the hospital.