Giardia is the most common parasitic infection in international adoptees, and is also frequently implicated in day-care center diarrhea outbreaks. Studies have shown that it is found in up to 20% of international adoptees, particularly older adoptees from Eastern Europe; in our experience it seems to come in clusters, averaging around 10-20% of our adoptees, and we do see it from China as well.
It's a microscopic flagellated protozoan parasite that is quite infectious (it can take as few as 10 cysts to cause infection), and it is typically spread by drinking contaminated water or fecal-oral transmission. So ... wash hands scrupulously after diaper changes, toilette, and before meals/food prep until giardia is ruled out, and don't have new arrivals share baths with other children at first.
Giardia can be asymptomatic, but symptoms often include loose, watery stools, with a certain foul-smelling greasy, floaty, frothy je ne sais quoi. Flatulence, cramps, bloating, and malaise can also be present. Chronic giardia may be associated with significant weight loss and failure-to-thrive. It also can cause secondary lactase deficiency - interfering with the intestine's ability to digest lactose. Even after successful treatment, loose stools can persist for a month or two. Cutting back on lactose, and supplementation with probiotics (unproven but likely to be safe) may help during this time period.
To diagnose giardia and other intestinal parasites, we recommend submitting 3 stool samples collected 2-3 days apart (preserved promptly after passage in a polyvinyl alcohol kit) for ova and parasite (O&P) examination, and one fresh (<1hr old) sample for Giardia antigen. Some refugee centers treat empirically with albendazole on arrival; we don't, because we prefer to know what we're treating, and because albendazole is ineffective against some of the common parasitic infections in adoptees. If the initial stool tests (remember, collect them 2-3 days apart to increase the chances of finding something) are negative but symptoms consistent with intestinal parasites persist, consider rescreening the stool; initial stool examinations miss infections in some children.
It's also important to do a "test-of-cure" giardia antigen test 1-2 months after treatment to confirm treatment success. If an adoptee tests positive for giardia, we treat, regardless of symptoms. You may not realize until later that the giardia was in fact causing symptoms, including malaise and poor growth; we also do this for the "public health" of the adoptive family.
Folks who don't see a lot of giardia often prescribe flagyl (metronidazole); in our experience this has an unacceptable failure rate. A better choice is Tinidazole, which was recently FDA approved for this indication, but has been in off-label use for some time, even in children <3yo. A convenient one-time 50mg/kg dose (max 2g) is what we use. It's mighty bitter, so mix with espresso syrup or other intensely sweet/flavorful option. See our medication tricks and tips for other ideas. Clark's Pharmacy in Bellevue, WA (425-881-0222) has it available in convenient dosing, is giardia savvy, and does mail order. Alinia is another recently approved medication for giardia that seems to be a reasonable alternative.
We don't automatically test or treat family members if giardia is promptly diagnosed in a new arrival, but if the child has been home awhile, if there are other young children around, or if anyone else is symptomatic then they should get checked as well.
Other stool parasites like Ascaris lumbricoides, Blastocystis hominis, Dientamoeba fragilis, Entamoeba histolytica, Trichuris trichiura, hookworms, and pinworms are also commonly identified in international adoptees. O&P results will often include non-pathogens, or commensals, which are not felt to cause illness and do not require treatment. However, they can be a sign that other parasites are present, and you should make sure that all 3 stool samples are evaluated. Links with good information about these and other, less familiar parasites are listed below.
Other Stool Parasite Resources:
- CDC Giardia Fact Sheet
- eMedicine Giardiasis Overview
- CDC Alphabetical Listing of Parasitic Infections (so many parasites to choose from, including Amebiasis, Ascariasis, Blastocystis hominis, Chilomastix mesnili, Cryptosporidium, Dientamoeba fragilis, Entamoeba coli, Enterobiasis (pinworms), Head Lice Infestation, Intestinal Roundworms, and Nonpathogenic Intestinal Amebae Infections)
- eMedicine Intestinal Protozoal Diseases (detailed medical overview of many common parasites, free registration required)
- A Field Guide to Emerging Enteric Protozoa - Contemporary Pediatrics (covers Dientamoeba fragilis, Blastocystis hominis, Entamoeba coli, and Cyclospora cayetanensis)