Tropical Medicine

TROPICAL MEDICINE –section of medical science, studying the questions of theory and practice of
health protection in tropical countries
PROBLEMS:
1. Development of doctrine of tropical diseases
2. Questions of hygiene of tropics
3. Оrganization of health саre in the tropics

TROPICS -
part of the earth's surface, located in the equatorial, subequatorial, tropical and subtropical climate zones between 23.5 degrees Northern latitude and 23.5° degrees South latitude. This zone includes Africa, Australia, India, Indochina, Indonesia, Iran, Iraq, Pacific Islands, South and Central America

EQUATORIAL AREA:
constantly high temperature (24 - 28°С), abundant rainfall (1500 - 3000 mm, in some places – up to 10000 mm). Thick multileveled forests, variety of flora and fauna (CONGO, KENYA)

SUBEQUATORIAL
ZONE:
constant high air temperature (22 - 25oC), change of dry and wet seasons. Domination of savanna, deciduous and evergreen forests, deserts and semi-deserts (SUDAN, CHAD and MALI)

TROPICAL AREA:
Winter temperature is not below 10°, in summer - 30 - 35°, distinguish the season of rains (summer) and season of drought (winter). Deserts, semi-deserts, savanna, deciduous forests (LIBYA, ALGERIA, EGYPT)

SUBTROPICAL AREA:
alternation of moderate (in winter) and tropical (in summer) temperature condition, monsoon, expressed differences in the rainfall. Deserts, semi-deserts and evergreen forests

FEATURES OF TROPICAL CLIMATE:
- High amounts of annual heat,
Oscillation of fallouts in the tropical forests within
3000 - 5000 mm\ year, in deserts - up to 200 mm\ year,
- Fluctuation of temperature about 50° in a day,
- There is large temperature drop and freezing in mountains

The FEATURES of tropical pathology depend on environment conditions and social factors

FACTORS OF THE NATURAL ENVIRONMENT:
TEMPERATURE
DIRECT INFLUENCE:
Violation of mechanisms, regulating body-temperature and electrolyte balance
Increased water consumption and high risk of intestinal infections
Desorder of water - salt metabolism (low acidity of gastric juice and decreased barrier function of the stomach
High frequency of colds (temperature variation and decreased barrier function of the upper RT)

INDIRECT INFLUENCE:
1. Wide distribution of numerous kinds of insects
(including bloodsucking)
Simulium
Phlebotomus
Anopheles

2. A hot climate assists the height of different types of plants and animals

3. Favourable conditions for existence of heat-loving causative
agents of infectious and invasion diseases (viruses of yellow,
Denge fever, filarias)
4. Optimal habitat for development of geogelmints (ascariasis,
trichuris and other)
5. High variety of special vectors dwelling in a temperate
climate (anopheles mosquitoes)
6. Existence of some vectors is possible only in the
conditions of tropics (tse-tse flies, kissing bugs and other)

Water
Reproduction of causative agents and preservation of them in the water (cholera, typhoid, dysentery, amebiasis, leptospirosis), shellfishes (schistosomiasis, dracunculosis), fishes (opisthorchiasis)
2. Development of special vectors - mosquitoes (malaria, filariasis, yellow
and denge fever), midges and other

The role of water increases due to next reasons:
Swimming in reservoirs. Using of reservoirs with a technical
purpose.
3. Drinking of unboiled water.
4. Use in food of raw water plants (mint,
chestnut, nut, lotus), fish, shellfishes.
5. Contamination of the rivers, ponds,
wells, soils by microbes and eggs of
helmints in the rain period.
6. Increase of concentration of the
contagious material in reservoirs in
the period of drought.

SOIL
Sourse of developing helmints - primary cause of disease
agricultural workers
2. Reservoir for multiplication of insects transmitting
infectious illnesses
SOLAR RADIATION
1. High frequency of sunburn and skin cancer
2. A radiation assists the sanation of environment

SOCIAL - ECONOMIC FACTORS
Low level of sanitary culture and illiteracy of
population (taking of unboiled water is a reason of 50% of infectious diseases, absence of the sewage system, dirty hands, bad housing terms)
High death rate especially among children
High birth-rate - 4-5% in a year.
Insufficient nourishment (is albuminous
starvation, hypovitaminosis and pellagra)

5. Occupation of the population
Leptospirosis and geohelminthiases more often registered among the peasants, brucellosis, anthrax, echinococal disease - among nomads. Loggers and hunters, as a rule, suffer from yellow fever and cutaneous leishmaniasis, plantation workers – from larva migrans.

6. Lifestyle, dietary habits, superstitions and customs
(presence of blood in the boys urine in
schistosomiasis is regarded as evidence of sexual
maturity)
7. Underdeveloped medicine, centralization
of hospitals in cities and their absence in the
villages, the remoteness of villages from each other
impede the provision of medical assistance
(per 1 physician 10 000 - 60 000 persons in rural
area)

There are ubiquitous and proper tropical
(millions of sick people: filariasis - 250 million; schistosomiasis - 270 million; leprosy 12 million)
Medical feature of tropical diseases
Infectious tropical diseases
Nonifectious tropical diseases
Tropical diseases of unknown origin
- Connecting with the
direct action of the environment;
- Connecting with the effect of natural and social factors;
- Genetic diseases;
- Other therapeutic diseases
Cardiac fibrosis
Cardio myopathy
Kaposhi sarcoma
- Malignant tumor
of lymphatic sistem
Registrated only in
tropics
In tropics and outside
the tropics

Peculiarity of the course of the tropical disease:
1. Unfavorable background
(insufficiency of power,
hypovitaminosis and others).
2. Massiveness of the infection.
3. Early age of primary infection.
4. The direct influence of the original
conditions of the environment.
5. Possibility to get several species of
parasites – polyparazitism
(2, 3 and more worms or worm
infections with bacterial infection).
6. Subclinical or obliterated course of
many diseases in the population of
endemic foci due to constant contacts
with pathogenic microorganism
and development of the immunity.

7. Severe course of the disease (meningococcal infection, measles, tuberculosis and other).
8. Chronization of many diseases.
9. Unusual course of some infections
(skin diphtheria –often,
faryngeal diphtheria - rarely ).
10. Presence of some diseases
prevents contamination of other
diseases (anemia S and C
prevents malaria infection).
11. Combination of some infections
provokes development of tumors
(EBV+malaria provokes Berkit’s
lymphoma).

Features the work of doctor in the tropics
1. In all cases of unclear fever appoint
antimalaria drugs.
2. In the treatment of all infectious
diseases simultaneously appoint
antimalaria drugs.
3. Before a surgical operation appoint antimalaria drugs.
4. Before the surgical operation examine the patient for
helminths and treat him.
5. After reviling a single parasite continue to search of
other pathogens

The most important diseases of the tropics
(according to WHO)
malaria
filariatosis
leishmaniasis
leprosy
schistosomiasis
trypanosomiasis