MAIN TROPICAL DISEASES
Amoebiasis (Amoebic Dysentery)
Causative Parasite: Amoebiasis is due to the ingestion of a unicellular parasite, the Entamoeba Histolytic. This mainly affects the intestinal tract.
Distribution: Although most prevalent as an endemic disease of tropical and sub-tropical countries, unhygienic disposal of excreta and primitive methods of water purification may result in its introduction into temperate zones.
Source of Infection: Water polluted by infected faeces is the commonest source of infection, hence the prophylactic importance of safe drinking water. Other sources of infection are, foods grown on soils manured by infected excreta, flies and infected food handlers.
Clinical features: Clinically the disease is characterised by an insidious onset, frequent febrile relapses and a tendency to chronicity. Diarrhoea is the outstanding symptom, but it may be absent. There is abdominal pain with blood and mucus in the stools.
Complications:
• Inflammation of the liver.
• Liver abscesses.
• Inflammation of the gall bladder and bile ducts.
Treatment: Consists of rest, diet and a course of therapy, which varies with the type of case.
Prophylaxis: No vaccination or inoculation is available, nor is there any chemical prophylaxis such as is used to prevent Malaria. General measures of hygiene should be observed.
Malaria
Transmission: Infection takes place through the bite of an infected anopheles mosquito and transmission of the parasite into the human blood stream.
Geographical Distribution: Variable.
Incubation period: The incubation period usually ranges from 10 to 35 days.
Morbidity: Malaria causes several million deaths each year.
Symptoms: An acute, sometimes chronic, often recurrent, febrile disease characterised by periodic paroxysms of chills followed by high fever and sweating due to the presence of parasites in blood. The early stage of the illness can very easily be confused with many other infectious diseases, the more so if this occurs after return to a temperate region where your doctor may not think immediately of the possibility of Malaria.
Prophylaxis: Preventive measures include use of insect repellent sprays to protect skin, screens on doors and windows, mosquito netting in bedrooms, sufficient clothing to cover as much as the skin surface as possible against mosquito bites (this is important after sundown). It is not possible to produce permanent immunity either chemically or by the use of vaccines. Therefore, chemical prophylactic drugs are only effective as long as they are taken regularly.
Treatment: Under medical supervision. Malaria can be fatal if treatment is delayed.
Therefore after having been in a malarial area, if you feel unwell or have an unusual temperature within four weeks of leaving the area, visit your doctor.
Typhoid and Paratyphoid Fevers
Definition: They are ingestion diseases characterised by high fever and intestinal symptoms.
Transmission: Typhoid fever is conveyed through water contaminated by sewage, through food grown in or gathered from water (e.g. shellfish and watercress) and through cooking utensils washed in such water. Paratyphoid fever is rarely transmitted through water, and few epidemics have been recorded. The disease is usually transmitted in food contaminated by carriers.
Incubation Time: From 7 to 21 days.
Geographical Incidence: The disease is likely to occur wherever the water supply is impure. Generally speaking the less satisfactory the sanitation, more prevalent is enteric fever. However, with use of adequate drugs, cases of death are now rare.
Symptoms: Vague symptoms of illness tending to increase in severity throughout the first week. Lassitude, frontal headache, general aches and pains, disturbed sleep, anorexia and thirst, abdominal discomfort, temperature rising to 40°C, diarrhoea with or without bleeding.
Precautions: Strict hygiene of food and drink.
Prophylaxis: Vaccination. The vaccination is not an international requirement for entry into any country. Vaccination is strongly recommended when travelling to regions of poor general hygiene.
Cholera
Geographical distribution: Outbreaks of the disease usually are explosive and limited.
Cholera is endemic in many areas of Asia.
Transmission: Cholera is spread by the ingestion of water and foods contaminated by the excrement of patients.
Incubation period: Short, usually 1 to 6 days.
Symptoms: Sudden onset. Initial symptoms are nausea, vomiting and diarrhoea, with variable degrees of fever and abdominal pain. If diarrhoea is severe the resultant dehydration may lead to intense thirst, muscle cramps and weakness.
Prognosis: In many cases the outlook depends largely on early and adequate therapy.
Prophylaxis: Strict measures of hygiene (food and drink) should be observed. In many countries cholera has been controlled by the purification of water supply and proper disposal of human excreta.
Dysentery
Definition: An acute infection of the bowel, characterised by frequent passage of blood and mucus diarrhoea accompanied by abdominal cramps, malaise and fever.
Incidence: Incidence is world-wide, but it is particularly common in hot climates.
Source of Infection: The source of infection is the excreta of infected individuals.
Organisms are spread from individual to individual by the direct faecal-oral route. Indirect spread by contaminated food and inanimate objects is common, but water borne disease is rare. Flies serve as carriers. Epidemics occur most frequently in overcrowded populations with inadequate sanitation. It is particularly common in younger children living in endemic areas, whereas adults of these regions are relatively resistant to infection and usually have less severe disease.
Incubation period: Very short, some hours to a few days.
Symptoms: Depend on severity. May have painful colicky diarrhoea. Raised temperature and vomiting may occur. The disease usually shows great individual variation.
Prophylaxis: There is no effective inoculation. Strict measures of hygiene (food and drink) should be observed.
Treatment: There are many effective medicines available for disinfection of the gastrointestinal tract. It is advised to consult a doctor.
Yellow Fever
Definition: An acute infectious virus disease occurring in tropical and sub-tropical zones.
Geographical Distribution: Particularly in tropical Africa and South and Central America. Unknown in Asia.
Incubation Period: 3 to 6 days.
Causative Organism: The virus that causes the disease is transmitted by the bite of a female mosquito, which previously has become infected through feeding on the blood of a patient during the early stages of an attack.
Symptoms: Characterised by sudden onset, fever with relatively slow pulse, the face is flushed, eyes infected, gums congested, tongue red and pointed. Vomiting and constipation are common. Jaundice appears after the third day.
Prophylaxis: Effective 10 days after vaccination and the immunity last for about 10 years.
Hepatitis A
Incidence: Hepatitis A is a common infection among travellers. The risk of contracting this viral infection is high wherever the water supply is impure and sanitation is not satisfactory (mainly outside western and northern Europe, USA, Canada, Australia and New Zealand).
Transmission: Hepatitis A may be acquired from food or water which has been contaminated by faeces or from direct contact with infected individuals. Person-to-person transmission is particularly common among children and between sexual partners.
Symptoms: Hepatitis A, formerly called infectious hepatitis, is rarely fatal, although most infected adults become quite ill, and many are unable to work for several weeks or months. Typical symptoms include malaise, fever, loss of appetite, gastrointestinal problems and jaundice and will appear 15 to 55 days after infection.
Prophylaxis: Travellers from industrialised countries are likely to be most susceptible to infection with Hepatitis A virus and should be vaccinated against before travelling to endemic areas.
Hepatitis B
Incidence / Prevalence: This infection is worldwide. It is prevalent in men who have sex with men and intravenous drug users, but the greatest number of cases result from heterosexual transmission. Persons with chronic Hepatitis B are at substantial risk of cirrhosis and hepatocellular carcinoma particularly when acquired early in life (up to 25 - 40%).
Transmission: HBV is usually transmitted by inoculation of infected blood or blood products or by sexual contact and is present in saliva, semen or vaginal secretion. Positive mother may transmit HBV during delivery.
Symptoms: About 30% of person has no signs or symptoms. Signs or symptoms include jaundice, fatigue, abdominal pain, loss of appetite, nausea, vomiting and joint pain.
Prophylaxis / Prevention: Hepatitis B vaccine is the best protection. Do not share personal care items that might have blood on them (razors, toothbrushes … etc.). Practice safe sex.
Consider the risk if you are getting a tattoo or body piercing. Do not donate blood, organs or tissue if you are Hepatitis B positive.
Disinsection of Aeroplane
In certain countries disinsection of the aeroplane cabin is required and must be carried out – refer to OM Part C, Airport Briefings. The standard reference aerosol used for the disinsection does not present a health hazard to humans if inhaled for short period.
Protective clothing for the hands and face is not necessary. Spraying must not be carried out while meals are being served. The best time for disinsection is 30 minutes before landing, provided this does not conflict with the requirements laid out of the respective country. The can(s) should be sprayed near the floor under the seats and/or into the overhead bins.
Causative Parasite: Amoebiasis is due to the ingestion of a unicellular parasite, the Entamoeba Histolytic. This mainly affects the intestinal tract.
Distribution: Although most prevalent as an endemic disease of tropical and sub-tropical countries, unhygienic disposal of excreta and primitive methods of water purification may result in its introduction into temperate zones.
Source of Infection: Water polluted by infected faeces is the commonest source of infection, hence the prophylactic importance of safe drinking water. Other sources of infection are, foods grown on soils manured by infected excreta, flies and infected food handlers.
Clinical features: Clinically the disease is characterised by an insidious onset, frequent febrile relapses and a tendency to chronicity. Diarrhoea is the outstanding symptom, but it may be absent. There is abdominal pain with blood and mucus in the stools.
Complications:
• Inflammation of the liver.
• Liver abscesses.
• Inflammation of the gall bladder and bile ducts.
Treatment: Consists of rest, diet and a course of therapy, which varies with the type of case.
Prophylaxis: No vaccination or inoculation is available, nor is there any chemical prophylaxis such as is used to prevent Malaria. General measures of hygiene should be observed.
Malaria
Transmission: Infection takes place through the bite of an infected anopheles mosquito and transmission of the parasite into the human blood stream.
Geographical Distribution: Variable.
Incubation period: The incubation period usually ranges from 10 to 35 days.
Morbidity: Malaria causes several million deaths each year.
Symptoms: An acute, sometimes chronic, often recurrent, febrile disease characterised by periodic paroxysms of chills followed by high fever and sweating due to the presence of parasites in blood. The early stage of the illness can very easily be confused with many other infectious diseases, the more so if this occurs after return to a temperate region where your doctor may not think immediately of the possibility of Malaria.
Prophylaxis: Preventive measures include use of insect repellent sprays to protect skin, screens on doors and windows, mosquito netting in bedrooms, sufficient clothing to cover as much as the skin surface as possible against mosquito bites (this is important after sundown). It is not possible to produce permanent immunity either chemically or by the use of vaccines. Therefore, chemical prophylactic drugs are only effective as long as they are taken regularly.
Treatment: Under medical supervision. Malaria can be fatal if treatment is delayed.
Therefore after having been in a malarial area, if you feel unwell or have an unusual temperature within four weeks of leaving the area, visit your doctor.
Typhoid and Paratyphoid Fevers
Definition: They are ingestion diseases characterised by high fever and intestinal symptoms.
Transmission: Typhoid fever is conveyed through water contaminated by sewage, through food grown in or gathered from water (e.g. shellfish and watercress) and through cooking utensils washed in such water. Paratyphoid fever is rarely transmitted through water, and few epidemics have been recorded. The disease is usually transmitted in food contaminated by carriers.
Incubation Time: From 7 to 21 days.
Geographical Incidence: The disease is likely to occur wherever the water supply is impure. Generally speaking the less satisfactory the sanitation, more prevalent is enteric fever. However, with use of adequate drugs, cases of death are now rare.
Symptoms: Vague symptoms of illness tending to increase in severity throughout the first week. Lassitude, frontal headache, general aches and pains, disturbed sleep, anorexia and thirst, abdominal discomfort, temperature rising to 40°C, diarrhoea with or without bleeding.
Precautions: Strict hygiene of food and drink.
Prophylaxis: Vaccination. The vaccination is not an international requirement for entry into any country. Vaccination is strongly recommended when travelling to regions of poor general hygiene.
Cholera
Geographical distribution: Outbreaks of the disease usually are explosive and limited.
Cholera is endemic in many areas of Asia.
Transmission: Cholera is spread by the ingestion of water and foods contaminated by the excrement of patients.
Incubation period: Short, usually 1 to 6 days.
Symptoms: Sudden onset. Initial symptoms are nausea, vomiting and diarrhoea, with variable degrees of fever and abdominal pain. If diarrhoea is severe the resultant dehydration may lead to intense thirst, muscle cramps and weakness.
Prognosis: In many cases the outlook depends largely on early and adequate therapy.
Prophylaxis: Strict measures of hygiene (food and drink) should be observed. In many countries cholera has been controlled by the purification of water supply and proper disposal of human excreta.
Dysentery
Definition: An acute infection of the bowel, characterised by frequent passage of blood and mucus diarrhoea accompanied by abdominal cramps, malaise and fever.
Incidence: Incidence is world-wide, but it is particularly common in hot climates.
Source of Infection: The source of infection is the excreta of infected individuals.
Organisms are spread from individual to individual by the direct faecal-oral route. Indirect spread by contaminated food and inanimate objects is common, but water borne disease is rare. Flies serve as carriers. Epidemics occur most frequently in overcrowded populations with inadequate sanitation. It is particularly common in younger children living in endemic areas, whereas adults of these regions are relatively resistant to infection and usually have less severe disease.
Incubation period: Very short, some hours to a few days.
Symptoms: Depend on severity. May have painful colicky diarrhoea. Raised temperature and vomiting may occur. The disease usually shows great individual variation.
Prophylaxis: There is no effective inoculation. Strict measures of hygiene (food and drink) should be observed.
Treatment: There are many effective medicines available for disinfection of the gastrointestinal tract. It is advised to consult a doctor.
Yellow Fever
Definition: An acute infectious virus disease occurring in tropical and sub-tropical zones.
Geographical Distribution: Particularly in tropical Africa and South and Central America. Unknown in Asia.
Incubation Period: 3 to 6 days.
Causative Organism: The virus that causes the disease is transmitted by the bite of a female mosquito, which previously has become infected through feeding on the blood of a patient during the early stages of an attack.
Symptoms: Characterised by sudden onset, fever with relatively slow pulse, the face is flushed, eyes infected, gums congested, tongue red and pointed. Vomiting and constipation are common. Jaundice appears after the third day.
Prophylaxis: Effective 10 days after vaccination and the immunity last for about 10 years.
Hepatitis A
Incidence: Hepatitis A is a common infection among travellers. The risk of contracting this viral infection is high wherever the water supply is impure and sanitation is not satisfactory (mainly outside western and northern Europe, USA, Canada, Australia and New Zealand).
Transmission: Hepatitis A may be acquired from food or water which has been contaminated by faeces or from direct contact with infected individuals. Person-to-person transmission is particularly common among children and between sexual partners.
Symptoms: Hepatitis A, formerly called infectious hepatitis, is rarely fatal, although most infected adults become quite ill, and many are unable to work for several weeks or months. Typical symptoms include malaise, fever, loss of appetite, gastrointestinal problems and jaundice and will appear 15 to 55 days after infection.
Prophylaxis: Travellers from industrialised countries are likely to be most susceptible to infection with Hepatitis A virus and should be vaccinated against before travelling to endemic areas.
Hepatitis B
Incidence / Prevalence: This infection is worldwide. It is prevalent in men who have sex with men and intravenous drug users, but the greatest number of cases result from heterosexual transmission. Persons with chronic Hepatitis B are at substantial risk of cirrhosis and hepatocellular carcinoma particularly when acquired early in life (up to 25 - 40%).
Transmission: HBV is usually transmitted by inoculation of infected blood or blood products or by sexual contact and is present in saliva, semen or vaginal secretion. Positive mother may transmit HBV during delivery.
Symptoms: About 30% of person has no signs or symptoms. Signs or symptoms include jaundice, fatigue, abdominal pain, loss of appetite, nausea, vomiting and joint pain.
Prophylaxis / Prevention: Hepatitis B vaccine is the best protection. Do not share personal care items that might have blood on them (razors, toothbrushes … etc.). Practice safe sex.
Consider the risk if you are getting a tattoo or body piercing. Do not donate blood, organs or tissue if you are Hepatitis B positive.
Disinsection of Aeroplane
In certain countries disinsection of the aeroplane cabin is required and must be carried out – refer to OM Part C, Airport Briefings. The standard reference aerosol used for the disinsection does not present a health hazard to humans if inhaled for short period.
Protective clothing for the hands and face is not necessary. Spraying must not be carried out while meals are being served. The best time for disinsection is 30 minutes before landing, provided this does not conflict with the requirements laid out of the respective country. The can(s) should be sprayed near the floor under the seats and/or into the overhead bins.
MAIN TROPICAL DISEASES
Reviewed by Aviation Lesson
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9:45 PM
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Reviewed by Aviation Lesson
on
9:45 PM
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