Giardiasis
Giardiasis is an acute or chronic parasitic infection of the gastrointestinal system caused by the protozoan Giardia lamblia. It is transmitted through the ingestion of contaminated food or water and can also spread through person-to-person contact involving fecal contamination. The symptoms of giardiasis can range from asymptomatic to more severe, including abdominal pain, cramps, flatulence, weight loss, and diarrhea, with a duration of one to two weeks, although some cases can become chronic. Treatment options include medications such as tinidazole, metronidazole, and furazolidone, with some cases resolving without intervention. Preventative measures emphasize the importance of strict hand-washing, especially in settings with young children, and purification of drinking water. Giardiasis is particularly prevalent in developing countries, affecting a significant portion of the population, while in developed regions, it affects a smaller percentage of adults and children. Historically, the pathogenic role of Giardia was established in the 1960s, and it is now recognized as a neglected disease, especially in low-income areas. Understanding giardiasis is essential for improving public health, particularly in vulnerable communities.
Giardiasis
ANATOMY OR SYSTEM AFFECTED: Gastrointestinal system
DEFINITION: An acute or chronic parasitic infection of the gastrointestinal system.
CAUSES: Parasitic infection
SYMPTOMS: Often asymptomatic; can include abdominal pain, cramps, flatulence, weight loss, diarrhea
DURATION: One to two weeks; occasionally chronic
TREATMENTS: Medication (furazolidone, metronidazole, paromomycin)
Causes and Symptoms
The parasite Giardia lamblia, which causes giardiasis, is a protozoan acquired through the ingestion of contaminated food or water. This organism can also be spread by person-to-person contact involving fecal contamination. It is among the parasites most commonly acquired by children in day-care centers and preschools.
After exposure, the before the onset of symptoms is one to two weeks. After infection, only 25 to 50 percent of affected individuals become symptomatic. Giardiasis is characterized by abdominal pain, cramps, flatulence, weight loss, and diarrhea, which in many cases may be chronic (of a duration longer than fifteen days).
Treatment and Therapy
Some cases of giardiasis are self-limited. The treatment of choice for giardiasis in the United States is a single oral dose of tinidazole. Metronidazole and nitazoxanide are alternative oral medications that require multiple doses over several days. Furazolidone and metronidazole are equally efficacious; the first may be more practical in children because of its availability in liquid form.
Giardiasis can be prevented by strict hand-washing, especially in those individuals who are in close contact with patients with or children still in diapers. Another important factor in preventing giardiasis is the purification of drinking water, which can be achieved through boiling or chemical decontamination. It has been demonstrated that breastfeeding protects infants against symptomatic infection.
Perspective and Prospects
G. lamblia was first observed by microscopist Antoni van Leeuwenhoek in 1675. It was once considered a harmless organism, but its pathogenic role was clearly established in the 1960s. This parasite is one of the most common protozoans able to infect humans.
Giardiasis is considered by many to be a neglected disease due to its greater prevalence in developing and low-income countries. According to the Centers for Disease Control and Prevention (CDC), giardiasis infects approximately 2 percent of adults and 6–8 percent of children in developed countries, compared to almost 33 percent of all people in developing countries. The World Health Organization (WHO) designated giardiasis a neglected disease in 2004, according to Lorenzo Savioli et al., but as of 2024 the disease is not included in its list of neglected tropical diseases (NTDs). However, the journal PLOS Neglected Tropical Diseases does list giardiasis as a major NTD within the scope of its subject matter.
Bibliography
Alan, Rick. "Giardiasis." Health Library, EBSCO Information Services, 11 May 2013, healthlibrary.epnet.com/GetContent.aspx?token=D39207C8-9100-4DC0-9027-9AC6BA11942D&chunkiid=11833. Accessed 1 Apr. 2024.
Berger, Stephen A., and John S. Marr. Human Parasitic Diseases Sourcebook. Jones and Bartlett, 2006.
Desai, Angel N. "Giardiasis." JAMA Network, vol. 325, no. 13, p. 1356, 6 Apr. 2021, doi:10.1001/jama.2020.10289. Accessed 1 Apr. 2024.
Despommier, Dickson D., et al. Parasitic Diseases. 5th ed., Apple Tree Productions, 2005.
Escobedo, Angel A., et al. "Giardiasis: The Ever-Present Threat of a Neglected Disease." Infectious Disorders—Drug Targets, vol. 10, no. 5, 2010, pp. 329–48.
"Giardia Infection (Giardiasis)." Mayo Clinic, Mayo Foundation for Medical Education and Research, 8 Nov. 2022, www.mayoclinic.org/diseases-conditions/giardia-infection/basics/definition/con-20024686. Accessed 1 Apr. 2024.
Hill, David R., and Theodore E. Nash. “Giardia lamblia.” Mandell, Douglas, and Bennett’s Principles and Practice of Infectious Diseases, edited by John E. Bennett et al., 8th ed., vol. 2, Elsevier, 2015, pp. 3154–60.
"Journal Information." PLOS Neglected Tropical Diseases, PLOS, journals.plos.org/plosntds/s/journal-information. Accessed 1 Apr. 2024.
"Parasites—Giardia." Centers for Disease Control and Prevention, US Dept. of Health and Human Services, 19 May 2022, www.cdc.gov/parasites/giardia/index.html. Accessed 3 Apr. 2024.
Roberts, Larry S., and John Janovy Jr.. Gerald D. Schmidt & Larry S. Roberts’ Foundations of Parasitology. 9th ed., McGraw-Hill, 2013.
Savioli, Lorenzo, et al. "Giardia and Cryptosporidium Join the 'Neglected Diseases Initiative.'" Trends in Parasitology, vol. 22, no. 5, 2006, p. 203–8.