INFECTIOUS HEPATITIS AND ITS PERVENTION

Identification and definition of Jaundice

A sub-acute or sudden febrile infectious  disease due to virus, characterized by a sudden onset abdominal discomfort, nausea, feeling to vomit and symptoms to hepatitis which is the main feature of this disease. Jaundice is normally present in this disease but may be absent. Serum hepatitis is transmitted through transfusion, vaccination,  and inoculation and not give to rise to initial gastrointestinal symptoms. Case fatality is low but case mortality is high and prolonged. The diagnosis is confirmed by various serological tests or even biopsy by liver puncture; serum enzyme and biopsy are the most reliable tests.

Causative organism 

It is due to a virus, out of them two are important. The virus of infective hepatitis is called virus A, and that of serum hepatitis is called virus B, and they are indistinguishable from each other in any away. However, sufficient evidence on clinical and epidemiological grounds to suggest that two infections are caused by 2 different members of the same family of viruses or different strains of the same virus affecting the liver cells. Virus of the serum hepatitis never find in faeces; but in a more or less close community. Serum hepatitis is spread by using an unsterilized needle for injecting the person after the inoculation of the carrier. Man possess no natural immunity, and incubation period is 25 days with a range of 15 to 50 days.In the case of serum hepatitis 90 days, may be prolonged to 60 to 160 days. Pregnant woman and alcoholics are more vulnerable to high morbidity and high mortality. One attack or childhood exposure to endemic infection confers immunity to certain extent. Virus hepatitis has a world wide distribution and during past years a number of out breaks occurred in India and other countries. Few cases occur throughout the year, but more incidence is in fly breeding seasons.

Prevention and control

A very high standard of environmental sanitation, control of fly breeding and personal hygiene are to be strictly maintained. Protection of water supply and its purification and efficient diary management to avoid unpolluted milk supply and attention to disposal of waste including sewage disposal. Sterilizing needles and syringes every time  when it used for injections.

On occurrence of a case patient should be admitted to hospital for correct diagnosis between infectious or serum hepatitis. So that correct control measures, specially in controlling the constant prevalence of sporadic cases in locally and prevent out breaks. It is not important to isolate the patient. he is kept apart and precautions are taken as for other food and water borne diseases. A case of infectious hepatitis never should be taken to a ward where there are acutely ill patients admitted. Flies should not gain access to stools, urine, sputum,etc.which are to be disinfected. A separate ward or wards are to be set apart in case of a epidemic out break occurs. Current and terminal disinfection should be carried out.

For families immune gamma globulin is good as a preventive measure. Personal hygiene should be maintained at high level. Strict anti fly measures are to be enforced. Attendance should take all precautions as required for the food and water borne diseases. As anything which damages the liver like alcohol should be avoided. Alcohol may increase the disease, it is advisable to with hold them from close contacts. Control food and drink. All source of water supply should be taken to protect, all sources of water from any likely pollution. Water should be taken from sources that are not liable to contaminate with excreta. Even super chlorination is not suppose to kill the virus, unless water is very efficiently clarified and an half hour contact is necessary before supply. Water should be boiled during an out break of jaundice. Strict inspection of sales of ice creams including manufacture and distribution,specially near to educational institutions.

ANIMAL BORNE DISEASES

Definition.

Zoo-noses is the state in which the infections initially affecting animals are transmissible to human beings and also some times the process may be reversed and some infections may pass from man to animals. WHO defines to those infections and diseases which are naturally transmitted between vertebrate animals and man plague, rabies/hydrophobia, anthrax, yellow fever, relapsing fevers, etc, are the some typical examples of such infections originally affecting animals and transmitted to human beings.

Type of reservoirs.

Most of the animal borne diseases start with host-sensitivity and through the stages of achievement of success in parasitism is the genesis of zoo-noses. Parasitism aims at self-preservation and a species propagation by obtaining sustenance from the host. So it attains tolerance and symbiosis to make zoo-nosies progressively more successful. More often the host is partially sensitive. When some vertebrate animal hosts are sensitive to parasites, some other animals are likely to be a tolerant or symbiotic host, so as to permit perpetuation of the parasite in nature. For example dogs are intensely sensitive to rabies virus; the wild Candida like the wolf , jackal or fox, which transmits this infection to dogs also suffer from rabies. The search for more tolerant host which can permit perpetuation of rabies virus in nature, with out themselves succumbing to the infection, has led to the discovery that Vampire bats, etc and some rodent species act as such hosts for rabies virus. Similarly, the urban rodents, who acquire plague infection sylvatic rodents, themselves die of the disease. Tolerant or symbiotic animal hosts are the permanent reservoirs of zoo-noses; the ones either sensitive or only partially resistant are semipermanent reservoirs of zoo-noses; and the ones which are more sensitive are the temporary reservoirs of zoo noses.

Important of the knowledge of animal borne diseases.

When an infection is known to be  animal borne and its temporary or permanent carrier is known, its control in human population becomes easy by either veterinarily controlling it among animals, by destruction of animals themselves, or by interrupting its transmission to the human population. The negative information is also important as it enables us to definitely exclude certain vertebrate from the possibility of being natural reservoirs. The knowledge of animal borne diseases enables us to study the parasite. and reactions and the behavior caused by it in the animal host during the pathogenic process. It is there after, leads us to form a picture of the natural history, remedy and how the disease affect  on the mankind. It also helps in finally diagnosing the otherwise intractable infection. For epidemiological studies, the search for animal borne diseases can be extended infinitely experimental transmission in a laboratory for determining the host range.

Some common animal borne diseases.

WHO has numbered more than 100 diseases constituting animal borne. 40 of them involve dogs and cats and 20 involve rodents of different types. The important examples of zoo-noses generally met with are the rodent borne infections such as plague, relapsing fever, rickettsiases, salmonelloses, worm infections, melloidosis, laptospirosis, rat bite fever, toxoplasmosis, tularaemia, etc.and so on. The primate infections like yellow fever and infective hepatitis and non pulmonary tuberculosis due to drinking of milk of an infected cow, brucellosis, Q fever and taeniasis, canine infections like rabies, leishmanaisis, and echinococcosis.Trypanosomiasis in Africa is also a zoo-noses. Taxoplasmosis is widespread in natural and its disease producing organism is symbiotic with many animal hosts. How man gets this infection is not yet known certainly, but dog is closely associated with man is implicated. Orinithosis is originally a disease of birds, specially in parrots, hawks, kites, etc. Psittacosis is the ornithosis of parrots transmitted to man. The virus of lymphocytic choriomaningitis is spread widely among mice but is transfered to man through a dog or cat due to his proximity to these animals. Anthrax is common farm animals and cattle and its spread to man may be due to the use of wool, hide or meat of infected animals. Some animal borne diseases are transmitted by arthropod vector species is more important means control the transmission of those diseases to human beings.

Prevention and control 

It is to eradicate the disease from human population by controlling natural ranges of animal borne diseases easier and earlier. For e,g.the bovine/intestinal tuberculosis strain was discovered to be the cause of human non-pulmonary tuberculosis infection and a search proved that the natural range for this infection was extremely narrow and almost confined to cows.A wide drive in the U.K. for raising non tuberculosis herds has been very successful that  at present there is no infection among the milking cows and hardly any bovine infection in human beings in that country. Similarly rabies and hydrophobia in many western countries have been almost eradicated by efficient caniculture. The larger the host range the wider should be the spread of infections and more difficult to eradicate. If it is confirmed definitely that there is no animal borne disease exists in respect of a particular human ailment, it leaves us free to concentrate all attention on the measures to control,prevent or eradicate the human reservoir,has happened in the case of malaria.

The general scheme of prevention and control of animal borne diseases may necessary to emphasis on one or more measures written below. We can control arthropod vector, protected the domestic animal from sylvatic disease, protect man from contact with the reservoir, domestic source and arthropod vectors or ectoparasites, protect food of man, water or other relevant articles of use from getting contaminated, destroy sylvatic or domestic sources,cure the domestic reservoir or source to the point of eradication enzootic or epizootic, search for the permanent reservoir in nature and and ruin it, and check the  migration of such reservoir or susceptible animals. Each of these methods has special application in a particular animal borne disease. In addition the international surveiliance is also required to control international transmission of animal borne infections.