Giardia lamblia

Az egysejtű élősködővel fertőzöttek fele tünetmentes, gyermekek esetében azonban szinte mindig tapasztalhatóak a tünetek.

Kórokozója a Giardia lamblia. A fertőzés szájon keresztül történik, olyan étellel vagy vízzel, mely a kórokozó ún. ciszta alakjával szennyezett. A lenyelt ciszták a patkóbélben alakulnak át kifejlett egyedekké (trophozoita). A trophozoiták a gazdaszervezet vékonybelének hámsejtjeire tapadva élősködnek, és kellő mértékben elszaporodva súlyos tápanyag-felszívódási zavart okozhatnak.

A giardiasis felléphet járványszerűen is, ha szennyvíz jut az ivóvízhálózatba, a klórozás ugyanis önmagában még nem pusztítja el a kórokozókat. Fokozott veszélynek vannak kitéve azok, akik forralatlan természetes (patak)vizet isznak, ugyanis a hordozó állatok is szennyezhetik a vizet. Giardiasis gyakrabban fordul elő homoszexuálisak körében is az oro-analis szexuális kapcsolat miatt.

• you have had diarrhoea for more than a week
• you have bloody diarrhoea or bleeding from your bottom

It's best to call rather than visit the GP surgery as you might have an infection that can spread easily to others.

Tell the GP if you have recently travelled abroad.

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Giardiasis occurs where there is inadequate sanitation or inadequate treatment of drinking water. Giardiasis is one of the causes of "traveler's diarrhea" that occurs during travel to less-developed countries, for example the Soviet Union, Mexico, Southeast Asia, and western South America. Giardiasis is a common cause of outbreaks of diarrhea in day-care centers because of the high probability of fecal-oral contamination from children; the children, their families, and day care center workers, all are at risk for infection. In fact, children are three times more likely to develop giardiasis than adults. Hikers exploring back-country areas who drink from contaminated freshwater lakes also are at risk for developing giardiasis. Individuals who practice anal/oral sex also may become infected.

Giardiasis Symptoms & Signs

Signs and symptoms of giardiasis can vary, and some people may be infected without showing any symptoms. Symptoms, when they occur, can last 2 weeks or longer. The most common symptoms are

• diarrhea,
• gas,
• fatty or foul-smelling stools (they may float), and
• stomach or abdominal cramping.

What signs and symptoms does giardiasis cause?

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The most common manifestations of giardiasis are diarrhea and abdominal pain, particularly cramping; however, diarrhea is not invariable and occurs in 60%-90% of patients. Other common manifestations include:

, with or without vomiting,
• malaise, and .

Fever is unusual. The severity of the symptoms may vary greatly from mild or no symptoms to severe symptoms. Stools may be foul smelling when the Giardia interferes with the absorption of fat from the intestine (malabsorption). The illness or the malabsorption may cause loss of weight.

Symptoms and signs of giardiasis do not begin for at least seven days following infection, but can occur as long as three or more weeks later. In most patients the illness is self-limiting and lasts 2-4 weeks. In many patients who are not treated, however, infection can last for several months to years with continuing symptoms. Children with chronic infection may fail to thrive. Some patients recover from their giardiasis, with or without treatment, but symptoms continue, perhaps because of a condition referred to as postinfectious irritable bowel syndrome. The cause of the continuing symptoms is not clear but may be due to bacterial overgrowth of the small intestine.

SLIDESHOW

How do medical professionals diagnose giardiasis?

The best single test for diagnosing giardiasis is antigen testing of the stool. For antigen testing, a small sample of stool is tested for the presence of Giardial proteins. The antigen test will identify more than 90% of people infected with Giardia. Giardia also can be diagnosed by examination of stool under the microscope for cysts or trophozoites; however, it takes three samples of stool to diagnose 90% of cases. Despite requiring three samples of stool, microscopic examination of stool identifies other parasites in addition to Giardia that can cause diarrheal illness. Therefore, microscopical examination of stool has value beyond diagnosing giardiasis, as it can identify and diagnose other parasites as the cause of a patient's illness.

Other tests that can be used for diagnosing giardiasis are collection and examination of fluid from the duodenum or biopsy of the small intestine, but these require tests that involve expense and discomfort. The string test is a more comfortable method for obtaining a sample of duodenal fluid. For the string test, a gelatin capsule that contains a loosely woven string is swallowed. One end of the string protrudes from the capsule and is taped to the patient's outer cheek. Over several hours, the gelatin capsule dissolves in the stomach, and the string uncoils, with the last 12 inches or so passing into the duodenum. In the duodenum the string absorbs a small amount of duodenal fluid. The string then is untapped from the cheek and is removed. The collected duodenal fluid is expressed from the string and is examined under the microscope. Although more comfortable than some of the other tests, it is not clear how sensitive the string test is in diagnosing giardiasis.

What is the treatment for giardiasis?

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The most common treatment for giardiasis is metronidazole (Flagyl) for 5-10 days. It has an efficacy rate of 75%-100%, but it often causes gastrointestinal side effects such as nausea and a metallic taste as well as dizziness and headache. Despite its effectiveness, metronidazole is not approved by the FDA in the U.S. for treatment of giardiasis.

Tinidazole has replaced furazolidone as the FDA-approved drug for treatment of the condition, and is highly effective at treating giardiasis (>90%). It also can be given as a single dose and is well tolerated. Furazolidone and Quinacrine are effective for treating giardiasis but are no longer available in the U.S. Albendazole and mebendazole are effective alternative agents, but these are not approved for used in the U.S. Paromomyin is less effective than other treatments.

Occasionally, treatment fails to eradicate Giardia. In such cases, the drug may be changed or a longer duration or higher dose may be used. Combination therapy also may be effective (for example, quinacrine and metronidazole).

Giardiasis is an infection in your small intestine. It’s caused by a microscopic parasite called Giardia lamblia. Giardiasis spreads through contact with infected people. And you can get giardiasis by eating contaminated food or drinking contaminated water. Pet dogs and cats also frequently contract giardia.

This condition can be found all over the world, according to the Centers for Disease Control and Prevention (CDC). However, it’s more common in overcrowded developing countries that lack sanitary conditions and water quality control.

G. lamblia are found in animal and human feces. These parasites also thrive in contaminated food, water, and soil, and can survive outside a host for long periods of time. Accidentally consuming these parasites can lead to an infection.

The most common way to get giardiasis is to drink water that contain G. lamblia. Contaminated water can be in swimming pools, spas, and bodies of water, such as lakes. Sources of contamination include animal feces, diapers, and agricultural runoff.

Contracting giardiasis from food is less common because heat kills the parasites. Poor hygiene when handling food or eating produce rinsed in contaminated water can allow the parasite to spread.

Giardiasis also spreads through personal contact. For example, unprotected anal sex can pass the infection from one person to another.

Changing a child’s diaper or picking up the parasite while working in a day care center are also common ways to become infected. Children are at high risk for giardiasis because they’re likely to encounter feces when wearing diapers or potty training.

Some people can carry giardia parasites without experiencing any symptoms. Symptoms of giardiasis generally show up one or two weeks after exposure. Common symptoms include:

You may have to submit one or more stool samples for testing. A technician will check your stool sample for giardia parasites. You could have to submit more samples during treatment. Your doctor may also perform an enteroscopy. This procedure involves running a flexible tube down your throat and into your small intestine. This will allow your doctor to examine your digestive tract and take a tissue sample.

In most cases, giardiasis eventually clears up on its own. Your doctor might prescribe medication if your infection is severe or prolonged. Most doctors will recommend treatment with antiparasitic drugs, rather than leaving it to clear up on its own. Certain antibiotics are commonly used to treat giardiasis:

is an antibiotic that needs to be taken for five to seven days. It can cause nausea and leave a metallic taste in your mouth.
• Tinidazole is as effective as metronidazole, and often treats giardiasis in a single dose.
• Nitazoxanide is a popular option for children because it’s available in liquid form and only needs to be taken for three days.
• Paromomycin has a lower chance of causing birth defects than other antibiotics, although pregnant women should wait until after delivery before taking any medication for giardiasis. This medication is given in three doses over the course of 5 to 10 days.

Giardiasis can lead to complications such as weight loss and dehydration from diarrhea. The infection can also cause lactose intolerance in some people. Children under 5 years old who have giardiasis are at risk for malnutrition, which can interfere with their physical and mental development.

You can’t prevent giardiasis, but you can lower your risk of getting it by thoroughly washing your hands, especially if you work in places where germs spread easily, such as day care centers.

Ponds, streams, rivers, and other bodies of water can all be sources of giardia. Don’t swallow water if you go swimming in one of these. Avoid drinking surface water unless it’s been boiled, treated with iodine, or filtered. Bring bottled water with you when you go hiking or camping.

When traveling in a region where giardiasis occurs, don’t drink tap water. You should also avoid brushing your teeth with tap water. Keep in mind that tap water can also be present in ice and other beverages. Avoid eating uncooked local produce.

Be cautious about sexual practices associated with the spread of this infection, such as anal sex. Use a condom to reduce the chance of contracting giardiasis.

Giardiasis infections usually last about six to eight weeks, but problems such as lactose intolerance can persist after the infection clears up.

Traitement et Prévention

Dans certains cas, la giardiase disparaît spontanément en environ 1 mois. D’autres personnes ont besoin de prendre des antibiotiques (par ex. le métronidazole*ou la paranomycine) pour raccourcir la durée de l’infection et pour tuer le parasite.

Comme l’affection est susceptible de se propager rapidement, il se peut que votre médecin vous suggère de traiter toute votre famille en même temps. Votre médecin peut également vous suggérer de prendre votre médicament pendant plus longtemps ou de changer votre médicament selon l’intensité de votre maladie. Il importe tout particulièrement que vous indiquiez à votre médecin si vous êtes enceinte, car certains médicaments servant au traitement de cette affection sont susceptibles de nuire à votre fœtus.

Enfin, il est très important que vous buviez suffisamment d’eau et de boissons riches en électrolytes (solutions contenant du sucre et des sels) parce que votre organisme perdra de l’eau à cause de la diarrhée. Parmi les signes de déshydratation, on observe une extrême fatigue, une sécheresse de la peau, de la bouche et de la langue, l’enfoncement des yeux dans les orbites et une très faible production d’urine ou de larmes.

Les enfants sont plus susceptibles de subir de la déshydratation que les adultes à cause de leur petite taille, les parents et les soignants doivent donc surveiller l’apparition des signes de déshydratation et s’assurer que l’enfant boit beaucoup de solution réhydratante. Les solutions orales de réhydratation que l’on peut se procurer dans les pharmacies (sous forme de liquides ou de paquets contenant de la poudre à mélanger avec de l’eau) sont un excellent moyen d’aider un enfant à rester bien hydraté. Si vous mélangez la poudre d’électrolytes avec de l’eau, assurez-vous que l’eau est propre pour éviter une réinfection.

Il existe plusieurs moyens efficaces d’éviter de contracter ou de transmettre cette infection. N’oubliez pas ces petits conseils :

• abstenez-vous de boire l’eau non traitée provenant de cours d’eau, de rivières ou de lacs même si elle vous semble très propre. Quand vous utilisez l’eau provenant de ces sources, faites-la bouillir au préalable pour 2 minutes (ou 3 minutes si vous vous trouvez en altitude);
• lavez bien vos mains à l’eau et au savon avant et après les repas, la préparation des aliments, le changement des couches et après avoir été aux toilettes;
• gardez votre enfant chez vous s’il est infecté et ne peut contrôler sa défécation. Il ne devrait pas fréquenter la garderie ni l’école;
• évitez d’avaler de l’eau lorsque vous nagez dans les piscines publiques ou les lacs, car les taux de chlore utilisés couramment dans les piscines ne tuent pas les kystes;
• essayez de manger des aliments bien cuits et chauds, et épluchez toujours les légumes et les fruits crus.

*Tous les médicaments ont à la fois une dénomination commune (un nom générique) et un nom de marque ou marque. La marque est l’appellation qu’un fabricant choisit pour son produit (par ex. Tylenol ® ). Le nom générique est le nom du médicament en médecine (par ex. l’acétaminophène). Un médicament peut porter plusieurs noms de marque, mais il ne possède qu’un seul nom générique. Cet article répertorie les médicaments par leur nom générique. Pour obtenir des renseignements sur un médicament donné, consultez notre base de données sur les médicaments. Pour de plus amples renseignements sur les noms de marque, consultez votre médecin ou un pharmacien.