Prognosis
Globally, most people infected with Giardia duodenalis are asymptomatic or minimally symptomatic. Less than 4% of people remain symptomatic for more than 2 weeks.
The efficacy of tinidazole and metronidazole is >80%.[66][73][76]
Asymptomatic patients
Treating asymptomatic patients, particularly children, is controversial.
In areas where G duodenalis is endemic, treatment may not be desirable because the children are likely to become rapidly reinfected following treatment.[85] Furthermore, the risks of periodic repeated treatment, as is performed for helminth infections, is not well defined.
Asymptomatic children in day care with excellent baseline nutrition status may not always need to be treated. However, asymptomatically infected children may excrete the organism for months, carrying it home to family members. This may initiate infection in the household and may even help maintain high levels of infection in a community. Recurrent diarrhea attributed to G duodenalis in day care warrants screening and treating all the children in the day-care setting. There is evidence that lactoferrin supplementation may lower prevalence of Giardia colonization among children, but this practice is not common.[86]
Faltering of growth and development
If infection contributes to faltering of growth and development, treatment may allow catch-up growth (even though reinfection may occur). One randomized controlled trial conducted in Bangladesh showed better weight-for-age and weight-for-height Z-scores, with improvement in small intestinal mucosal function, as a result of treatment.[87] Drugs such as albendazole might be useful in these settings; however, the requirement for 5-day dosing may be difficult to complete in many situations.
Chronic giardiasis
Patients with chronic giardiasis, whether they are immunodeficient or not, are frequently refractory to standard drug treatment and may require longer repeat treatments, higher doses, or combination therapy.
Use of this content is subject to our disclaimer