Parasite infection

Parasites is a generic term for microscopic organisms that absorb nutrition from other living host organisms. The animal parasites are divided into endo- and ectoparasites, depending on whether the live inside the host or on its outside. Endoparasites, therefore, are amoebas, flagellates, worms, and protozoa. Ectoparasites are lice, mites, and ticks. In a global sense, parasite infections are most common and most dangerous forms of infection - especially bilharziasis, filariasis, and malaria.
Parasites can be an overlooked cause of many sufferings and diseases. A parasite attack can manifest itself as depression, lack of energy and loss of appetite - or exaggerated appetite, loathing of food, stomach ache, skin diseases, headache, and general malaise. People who are infected with parasites easily risk being misdiagnosed; especially because parasite attacks can also result in mental sufferings.

Dysentery is a life-threatening colonic infection caused by either amoebas (Entamoeba histolytica) or bacteria (also see "Shigella dysentery" under "Bacterial infections in general"). You can get infected with amoebic dysentery through polluted water, raw vegetables, or food that has been prepared under poor hygienic conditions. The incubation period varies from 1 to 7 days.
The cystic form is the infectious one.
Some amoeba species gnaw their way through the intestinal wall and can spread to other organs such as the brain, liver, and lungs. Amoebic dysentery can present itself in several ways: There are cases without symptoms in which the carrier excretes cysts and is unaware that he/she is spreading the infection. Even though the infected person in this case does not feel ill, the disease can suddenly break out.
The symptoms can manifest themselves as periodic, strong diarrhoe that can be bloody, porridge-like, smelly, and/or slimy. Moreover, stomach pains and fever can occur and the disease can have a destructive effect on the liver and colon. The disease is most prevalent in the tropical areas of Asia and Africa.
Bilharziasis (Schistosomiasis or Snail fever)
An infection with small worms (schistosoma) which usually infect the tissues and blood vessels around the bladder and intestine and in some cases also wander to other parts of the body, particularly the liver.
The infection is transmitted through water when infected people urinate or defaecate in the water. The eggs present in the urine or faeces hatch in the water and the small worms then invade the freshwater snails in which they propagate many times. After a latent period they leave the snail and penetrate the skin of humans.
The immediate symptoms can be rashes, reddening, and ithing skin (swimmer's itch). After a couple of weeks, other symptoms appear, such as fever, tiredness, and allergic reactions. The adult worms lay eggs that irritate the intestine and bladder. Later on in the course of the disease, stomach ache, diarrhoea, and bloody urine often occur.
The infection is common in most parts of Africa, Latin America, the Middle East, and the Far East. It cannot be transmitted directly from one person to the next, however, but is transmitted through a certain snail that is only present in fresh water. The only way to get infected, therefore, is through drinking unboiled lake water or through bathing in freshwater lakes.
Chaga's disease
Also called American trypanosomiasis. Is caused by the protozoan Trypanosoma cruzi which is transmitted by bloodsucking insects called kissing bugs. The parasite enters the kissing bug when the bug sucks blood from the infected person and then moves into the digestive system of the bug. When the kissing bug then sucks blood from another person, the increased abdominal pressure triggers it to empty its excrements on the skin and the parasite then enters the human host through the kissing bug's bite.
An infected bite can cause swelling and locally swollen lymph nodes and it can also result in fever. In the long term, the intestinal muscles might be damaged which will cause constipation and problems swallowing. If left untreated, permanent damage to the brain and heart can follow. The disease can be life-threatening.
The kissing bug can be found in several areas of Central- and South America: Argentina, Bolivia, Brazil, Chile, Peru, and Venezuela.
Cryptosporidium
is a single celled parasite which lives in the intestines of many mammals (especially cattle), fish, and crustaceans, and is excreted in faecal matter. One is infected if one comes into contact with infected faeces or contaminated drinking water, bath water, or food.
There are many types of Cryptosporidium. Humans are most often infected by Cryptosporidium hominis, which can spread from person to person. Cryptosporidium parvum spreads from animals to people.
The symptoms after infection are not always serious, but can give rise to permanent problems if it is not treated. These problems include diarrhoea, stomach pain, nausea, and weight loss.
Elephantiasis
Elephantiasis is caused by filariae transmitted from mosquitoes to humans. The disease occurs because the lymphatic vessels are being clogged with worms so that lymphatic fluid cannot be drained from a specific area of the body - e.g. an arm or a leg. This area then violently swells up and in time obtains an "elephant-like" appearance in both size and skin structure.
The filariae make the subcutis become thickened and hard because it is destroyed by the large pressure of fluid from the inside. Elephantiasis most often affects the legs but can also affect the scrotum, penis, arms, and breasts. Tourists who only stay for a short while in the tropics are only rarely infected because it takes repeated bites by infected insects to provoke a definite infection.

These are larvae from several roundworm species which infect through black flies, mosquitoes, stable flies, and water fleas. They are the cause of a number of diseases - especially in the tropics - e.g. filariasis, which can cause lymphoedema, elephantiasis, and onchocerciasis (river blindness). Many kinds of roundworms (nematodes) have filariae as part of their lifecycle: The nematodes Wuchereria bancrofti, Brugia malaye, Onchocerca volvulus (which causes river blindness), and Loa loa are the most important and most common ones.
The mature roundworms live in the connective tissues and the lymphatic system. They crawl around and place themselves under the skin or in the lymph nodes and lymphatic vessels. When the worms are located under the skin, they can give rise to nodes and rashes.
In humans, the worm produces the filariae - finely filamentous worms - that circulate in the body with the blood or lymph. Filariae cannot, however, develop into mature worms in humans; this can only be done in insects. Therefore, when an infected person is bitten by a fly or mosquito, the insect sucks blood containing filariae that develop into mature worms in the mosquito. Then, when the mosquito bites another person, the mature worm is transmitted further. This process requires quite a lot of warmth which is the reason for the diseases primarily existing in the tropics - particularly in Africa, Asia, and South America.
Both the mature worms and the filariae can cause disease. The incubation period can last up to 6 months or more and the symptoms can be highly individual - from fever, shivers, and headache, to blindness and elephantiasis.
The diseases rarely affects tourists staying in the tropics for a short period of time, but several hundred million people worldwide are infected with this parasite.
Giardiasis (Giardia intestinalis)
Giardia Lamblia is one of the most frequent microscopic intestinal parasites and is mostly transmitted through food and drinks polluted with faeces. It spreads in swimming pools and salt water and through contact between people (because of poor personal hygiene). The infection takes place under poor hygienic conditions through long lived cysts in the faeces in which the parasite has encapsulated itself in order to resist the elements.
It exists in the intestine and can cause chronic or recurrent diarrhoea and colic - particularly in children - and stomach ache. The symptoms may disappear for a period only in order to return and the disease can become extremely prolonged. The stools are yellowish, smelly, and filled with bubbles - and distention of the stomach and flatulence are common symptoms. Nausea and loathing of food is another typical sign and the person affected could lose 10 - 20 kg. (20 - 40 pounds).
Hookworms (Ancylostomiasis)
The germs (Anchylostoma duodenale or Necator Americanus) are transmitted via earth polluted with human faeces. The larvae penetrate the feet of the people stepping on them and find their way to the first part of their small intestine, the duodenum, in which the larvae cause small wounds. The affected person often loses a lot of blood resulting in anaemia. Hookworms are responsible for many deaths in the tropics.

Is caused by biting of the sand fly and since it attacks the internal organs (bone marrow, liver, lymph nodes, and spleen) and can invade the immune system cells, it can be fatal if it is not being treated. The incubation period is a couple of months. The symptoms are anaemia, periods of fever, large weight loss, swollen lymph nodes, and an enlarged spleen. The disease occurs in Brazil, Africa, the Greek mainland, the South of France, and the South of Spain.

Leishmaniasis is an infection caused by a parasite (Leishmania donovani) that is transmitted with the sand fly (Phlebotomus). As many other stinging insects, the sand flies are particularly active in the time between sundown and a couple of hours after sunrise. The disease is quite rare in short term tourists. There are several types and subtypes of this disease; the most important ones are Kala Azar and Oriental sore.
Malaria
See the separate article on Malaria.

A couple of weeks or months after having been bitten by the sand fly, callosities and nodes in the skin develop which will eventually turn into wounds or boils. Most often, they are harmless and heal by themselves, but if they are not treated, they will leave behind some disfiguring scars. The disease can be observed in Asiatic Russia, Costa del Sol, Mallorca, the Greek Archipelago, and in the Middle East, North Africa, and in many tropical- and subtropical areas.
The last type of Leishmaniasis is most often observed in the area around the Amazon; in Brazil, Mexico, and the rest of South America. This disease starts with callosities of the skin - just like in Oriental sore - after having been bitten by a sand fly. However, the ulcerations now appear at the very beginning. The infection will most often heal by itself without any particular permanent damage - but there is a great risk of disfiguring scars as well.
Pseudomonas infection
An elaborate article is being prepared.
Rickettsia infections
Rickettsiae are microorganisms that are being transmitted by blood-sucking insects like ticks, fleas, lice, mites, and bugs. The microorganisms are very small and cause several potentially fatal diseases.
The different rickettsia diseases can be found in different parts of the world. The most known are:
Trench fever
Scrub typhus (Rickettsia tsutsugamushi) in South East Asia (mites).
Typhus fever (Rickettsia Prowazeki) in Africa, Asia, Australia, Europe, and the Middle East (lice).
Q fever (Coxiella burnetii).
Rocky Mountain spotted fever (Rickettsia ricketsii) in northern South America and the USA (blood mites/ticks).
The most important of these are Scrub typhus, Typhus fever, and Rocky Mountain spotted fever.
General symptoms are fever, shivers, vomiting, and rashes.
Of course, there are other kinds of fever than the ones mentioned here.
The diseases do not pose a large threat to short term tourists, but people who like hiking in the wilderness, the jungle, and the wild should be aware of these diseases.
River blindness
River blindness is caused by a filaria parasite that is being transmitted to humans from mosquitoes living by the streams in Africa and South America. The disease is caused by a massive infection with Onchocerca volvolus. The mosquitoes only sting during the day and after a couple of months, a node develops under the skin followed by a rash and itching. If the disease is not being treated at this stage, the parasites can attack your eyes and cause blindness.
Sand flies
See under "Kala Azar", "Oriental sore", "Leishmaniasis".
Sand fleas
The insects suck blood. The female is capable of penetrating the human skin and laying her eggs.
Scabies
Scab mites are mostly transmitted through dirty towels, cloths, bedclothes, etc. The scab mite digs clefts in the superficial layers of the skin and then lays its eggs here causing terrible itching - especially at night when you are being warmed by blankets and duvets.
Sleeping sickness (Trypanosomiasis)
A very rare but incredibly dangerous disease that occurs in many African countries around the equator (20 degrees to the north and to the south, respectively). The risk of being infected as a short term tourist is extremely small.
The disease exists in two forms; the Gambian and the Rhodesian one which are both fatal. The symptoms of the two forms are quite similar; however, they develop faster in the Rhodesian sleeping sickness where the disease can also attack the heart and cause the infected person to die of cardiac arrest.
Sleeping sickness is caused by a parasite that is transmitted to humans by bites of an infected tsetse fly. The way of infection is as follows: When a fly sucks blood from an infected person, the parasite is being sucked up as well. Then, when the fly bites another person, the parasite is being injected into that person. The fly has a special preference for moving targets. Only 1% of the flies in the most severely affected areas carry the parasite.
The disease is most common in rural areas with cattle or wild animals. The Gambian sleeping sickness is spread with the tsetse fly that lives and breeds in shady waters, e.g. rivers and lakes on the savannah of West Africa. It is being transmitted by the fly biting people collecting water etc. by the waters.
Many wild animals on the savannah carry the Rhodesian sleeping sickness so both people on safari and fishermen and hunters should be careful.
The incubation period is normally 10 - 20 days - but it can be up to a year after which a red, warm, and painful swelling appears on what was once the bite. Then, a fever attack, severe headache, and swollen glands occur. Moreover, swelling of the joints, joint pain, and rashes can occur. Subsequently, the parasites can invade the nervous system and - perhaps years later - be the cause of depression, drowsiness, confusion, impotence, cramps, paresis, lethargy, and tiredness causing you to sleep a lot - also during the day.
At this early stage, sleeping sickness can be treated conventionally. If treatment is not initiated, however, unconsciousness (coma), epileptic seizures, and death may ensue. Sleeping sickness causes millions of deaths in Africa.
Water fleas:
See under "Filariae".