Sound advice about travel-related diseases
Planning to have a jungle holiday? If so, there are some precautions you should take to ensure that you enjoy the trip and are free of travel-related illnesses, in particular maladies that may come from your adventure.
Dr Pratap Singhasivanon, associate professor and dean of the Faculty of Tropical Medicine, Mahidol University, noted malaria tops the list of diseases that afflict returning travellers showing up at the Hospital for Tropical Diseases for treatment.
According to Dr Pratap, people contract malaria, an infectious disease, with the bite of an infective female anopheles mosquito (or yung kon pong). Occasionally, the ailment can also be transmitted by blood transfusion, organ transplantation, needle sharing and syringes contaminated with infected blood.
Unlike a cold or flu, malaria doesn't spread from person to person. In other words, people cannot get malaria from normal contract with malaria-infected person.
This insect-borne fever is especially prevalent in tropical countries including Thailand. The areas of potential risk to malaria in Thailand are along the border provinces, particularly in hilly and forested areas as well as rivers and streams. Provinces where the highest incidence of malaria is found are Kanchanaburi, Chanthaburi, Trat, Sa Kaeo, Ratchaburi, Tak, Chumphon, Prachuap Khiri Khan, Songkhla, Narathiwat, Ranong, Yala and Mae Hong Son.
Apart from the usual characteristics of chill, a fever and sweating, patients with malaria may exhibit other symptoms including fatigue, headache, muscle pains, vomiting and loss of appetite. They may be associated with anemia and jaundice, yellow colouring of the eyes and skin. The symptoms can develop as early as a week after the exposure but, in some cases, it may take months or years.
Malaria infections with Plasmodium falciparum, in particular, may cause acute disease leading to seizure, unconsciousness, kidney failure, acute respiratory disease syndrome, coma and death.
"Malaria is curable if a patient receives accurate diagnosis and prompt treatment. It can be treated effectively early in the course of illness. Delay in treatment can lead to serious or even fatal outcomes," Dr Pratap said. As malaria in Thailand is the multi-drug-resistant strain, anti-malaria drugs aren't recommended. Travellers should avoid over-the-counter anti-malaria drugs.
"The drug may have unwanted side effects. The best advice to prevent malaria is to avoid getting bitten by mosquitoes. Consult a doctor right away if you develop a fever or illnesses right after returning from a jungle trip and tell him or her of your travel. Malaria may be suspected and considered," the doctor said.
Another common ailment that travellers may carry back from jungle travel is scrub typhus. Less-well known, the disease is transmitted by some species of chigger (rai on) which can be found in areas of scrub vegetation where rodents live. This mite-borne infectious disease can also be prevalent in such areas as riversides, rainforests and mountain deserts. It's quite common in the rainy season.
People with high occupational risks for the illness include patrol soldiers and police, farmers, wildlife professionals and forest navigators.
Cases of scrub typhus have been found in all regions of Thailand. "While the disease is common, especially in northern Thailand, it is often under-reported," said Dr Pratap.
When bitten by infected chiggers, travellers may develop symptoms including fatigue, high fever, heavy headache, cough and red eyes. Some patients may develop a nasty rash.
"The bite of chigger, in particular, may leave black eschar, (similar to a cigarette burn injury) in some patients, and it is up to the doctor to make the diagnosis," Dr Pratap said.
If the condition's left untreated properly, the patient may experience a high fever for a couple of weeks. After that, the body may heal itself in some cases. Unfortunately, complications may mean the inflammation of vital body parts, including lung tissue, known as pneumonitis, brain (encephalitis) and heart muscle (myocarditis), that may lead to death in some patients. To confirm precise diagnosis of the disease, patients need to have blood and laboratory tests.
"With the use of antibiotics, the illness can be effectively treated," Dr Pratap stressed. "Travellers should wear clothes that cover most of the body, in particular the lower part, to help prevent the bite."
When having a jungle holiday, the doctor continued, it's possible for long-term travellers to be bitten by land leeches.
Of all the species of land leech known to us, only four or five can bite. When they feed, they use their anterior suckers to connect to a host. They use mucus and suction to stay attached and secrete an anti-clotting enzyme called hirudin, into the host's blood stream. After they become full, they will detach and move away.
"When feeding, they release an anesthetic so that a host or person will feel numb. One easy way of removal is to use a fingernail or flat object to break the seal of the oral sucker at the anterior end of the leech, then repeat with the posterior end and strike it away," Dr Pratap said.
The bite of a leech normally doesn't pose a threat. However, bacteria, viruses and parasites from previous blood sources may linger on in a leech and be retransmitted to humans. And some people may suffer severe allergies from leech bites that require urgent medical care.
Trekkers, meanwhile, may often feel the need to walk barefoot, which puts them at a potential risk of infection by hookworm that live in animal faeces. The mouth of the worm has sharp hook-shaped teeth that pierce the skin of the human host.
One important thing: don't underestimate the risk of leptospirosis (the so-called "wee rat problem") that can be contracted through exposure to the urine of infected animals including rats, particularly in inundated areas.