Tularaemia is an acute infectious disease that affects humans and animals and is caused by bacteria. This disease belongs to a group natural hot spot infections.
Etiology
Tularaemia is caused by bacteria – Francisella tularensis, which is small, gram-negative, aerobic, immobile and asporogen coco-bacyl. It is resistant in the environment, and held in carcasses of dead animals, in raw skins, soil, surface water and food products. This bacteria is resistant to low temperatures, while high temperatures rapidly inactivated it, and it is most sensitive to chlorine preparations for disinfection.
Epidemiology
Tularaemia is primarily a disease of many types of wild rodents, which are a reservoir of the disease. There are over 100 species worldwide, of which the most important are the domestic and field mice, rabbits, rats, water rats, squirrel, beaver, raccoons, and coyotes, foxes and many other animals, also in sheep, cats, dogs and pigs.
Among rodents the disease spreads mostly through ticks and lice that parasitize the rodents (sometimes through mosquitoes), as well as through contaminated water and mud (infected rodents are removing bacteria in the environment through urine and faeces).
Men may be infected with tularemia after all known epidemiological routes of transmission:
- Contact
Sufficient direct contact with skin or mucous membrane with tissue or blood of an infected animal during skinning, cutting meat, preparation of meals or just touching.
- Transmission
The infection is transmitted by hard-bodied ticks(family Ixodidae). It includes important disease vectors of animals and humans (tick-borne disease). The infection is caused trough ticks of insects, lice, and other insects or contact with their fluids (feces and urine).
- Respiratory way of infection
Infection is occured by inhalation of dust contaminated with germs of tularemia.
- alimentary way of infection
Infection occurs after drinking contaminated water (with faeces and urine, as well as dead rodents) or consumption of contaminated food (usually after undercooked meat from rabbits or other animals). It is thought that rabbit meat can remain infectious after freezing, which takes even several years.
Because tularaemia is a zoonosis, it usually affects people who are occupationally exposed to greater risk, such as hunters, fishermen, pastoralists, foresters , field workers and housewives.
After tularaemia it remains a solid immunity, but its duration is not known and there is an opportunity to reinfection.
Distribution
Tularaemia is a disease that is widespread in the Northern hemisphere of the Earth. This area covers the entire northern part of the Eurasian continent and North America, as well as a small part of Latin America (Mexico and Venezuela).
The existence of natural hotspots of the disease in the country was first discovered by Jh. Heneberg and his associates in 1968, when they isolated strains that caused tularemia among wild rodents.
The first cases of the disease in our country were in the epidemic of tularemia in the village Mitrašinci, near Berovo in 1995. 31 people has suffered In the epidemic. Next, in 1996 were registered five individual cases of tularemia in Berovo in the villages Mitrašinci(1),Robovo (1) and 3 cases in Budinarci.
In 2010,there was registered another outbreak of tularemia in Gostivar, mostly in the village of Vrapciste,which ended with a total of 20 patients. In 2011 was registered a sporadic case of an infected person from Skopje.
Clinical signs and symptoms (manifestation)
Depending on the localization, ie the site of penetration of bacteria in humans, tularaemia can manifest in several different clinical forms: glandular, ulceroglandular, oculoglandular, oropharyngeal, lung, intestinal and typhoid (generalized) form.
In all clinical forms, after 3-7 days of incubation, the beginning of the disease is acute, with the general infectious syndrome: fever, temperature, sweating, intense headaches, pain in the body and general weakness. The illness usually lasts 2 to 4 weeks.
- glandular form – with usually swollen lymph nodes, but without an ulceration.
- ulceroglandular form – is characterized by an inflammatory reaction of the skin, forming a papule which ulcerate and regional lymphadenopathy. Lymph nodes necrosis, and then comes to their sclerosation, but can often be full with pus.
- Oculoglandular tularemia is the rarest form of tularemia. Symptoms include pain, photophobia, intense ocular congestion, itching, lacrimation, edema of the ocular conjunctiva, and mucopurulent discharge.
- Oropharyngeal form – is manifested in the form of inflammation of the oral cavity, throat or tonsils (which can remain necrosis and deep defects) and swelling of the pharyngeal lymph nodes.
- Pulmonary form – a primary pulmonary disease, which occurs in the form of bronchitis and bronchopneumonia.
- Intestinal form – characterized the occurrence of abdominal pain, vomiting, diarrhea.
- typhoid or generalized form – high febrility (T), severe general intoxication typhoid condition, swelling of the spleen and rash.
Diagnosis
In regions where tularaemia is endemic, the diagnosis of the disease is easily set, and it is based on clinical and epidemiological survey (history of tick bite, exposing contact with potentially diseased animals or rodents, as well as exposure to potentially contaminated water or food). The Laboratory diagnosis are extremely important for the correct diagnosis. It is used the method of isolation of Francisella tularensis from pus points glands, blood or sputum, and agglutination test. Also, other tests, such as tests of mikroaglutination, haemagglutination test, and the ELISA test.
Treatment
Antibiotics completely changed the course and prognosis of the disease. Streptomycin and Tetracycline are the choice in the treatment of infected tularemia. Chloramphenicol- can also successfully replace tetracyclin, erytrocyclin and quinolones. As symptomatic therapy it is used analeptics, analgesics, rehydration and possibly transfusion.
Prevention and Suppression
In case of epizootic, in the settlements should be implemented appropriate agro-technical and sanitary prophylactic measures, as well as health education and public information.
People should avoid any contact with ticks during the stay in nature and use repellents or other type of protection (wearing gloves, boots, masks), especially those due to the nature of their profession or recreational, also people who handle with animals and their products.
Do not touch wild rodents and animals that do not run away from people, because it is a sign of their sickness.
Do not use for food meat (especially rabbit meat), if it has a suspicious origin, or if you know that currently existed epizootic, wheere hunting should be forbidden.
Avoid drinking and bathing in water that is suspected to be contaminated.
The most effective prophylaxis is application of mercury, antitularemia vaccine for people who are at high risk. By giving the vaccine, the epidemic is interrupted for 10-15 days after vaccination.
The vaccine remains solid and long-lasting immunity, and if it needs, it can be implemented a revaccination.
