GeneHealth - Your precision medicine

Giardiasis

Disease Details

Family Health Simplified

Buy Membership

Description: Giardiasis is an intestinal infection caused by the parasite Giardia lamblia, leading to diarrhea, abdominal cramps, and nausea.
Type: Giardiasis is an intestinal infection caused by the protozoan parasite Giardia lamblia. It is not a genetically transmitted disease; rather, it is acquired through ingestion of the parasite, typically via contaminated water or food, or through person-to-person contact.
Signs And Symptoms: Symptoms vary from none to severe diarrhoea with poor absorption of nutrients. The cause of this wide range in severity of symptoms is not fully known but the intestinal flora of the infected host may play a role. Diarrhoea is less likely to occur in people from developing countries.Symptoms typically develop 9–15 days after exposure, but may occur as early as one day. The most common and prominent symptom is chronic diarrhoea, which can occur for weeks or months if untreated. Diarrhoea is often greasy and foul-smelling, with a tendency to float. This characteristic diarrhoea is often accompanied by a number of other symptoms, including gas, abdominal cramps, and nausea or vomiting. Some people also experience symptoms outside of the gastrointestinal tract, such as itchy skin, hives, and swelling of the eyes and joints, although these are less common. Fever occurs in only about 15% of people, in spite of the nickname "beaver fever".Prolonged disease is often characterised by diarrhoea, along with malabsorption of nutrients in the intestine. This malabsorption results in fatty stools, substantial weight loss, and fatigue. Additionally, those with giardiasis often have difficulty absorbing lactose, vitamin A, folate, and vitamin B12. In children, prolonged giardiasis can cause failure to thrive and may impair mental development. Symptomatic infections are well recognised as causing lactose intolerance, which, while usually temporary, may become permanent.
Prognosis: In people with a properly functioning immune system, infection may resolve without medication. A small portion, however, develop a chronic infection. People with an impaired immune system are at higher risk of chronic infection. Medication is an effective cure for nearly all people although there is growing drug-resistance.Children with chronic giardiasis are at risk for failure to thrive as well as more long-lasting sequelae such as growth stunting. Up to half of infected people develop a temporary lactose intolerance leading to symptoms that may mimic a chronic infection. Some people experience post-infectious irritable bowel syndrome after the infection has cleared. Giardiasis has also been implicated in the development of food allergies. This is thought to be due to its effect on intestinal permeability.
Onset: For giardiasis, the onset of symptoms typically occurs 1 to 3 weeks after exposure to the Giardia parasite.
Prevalence: The prevalence of giardiasis varies widely by geographic region. In developed countries, it is estimated to affect about 2% of the population. In developing countries, the prevalence can be much higher, affecting as many as 20-30% of the population. Factors such as poor sanitation, close contact with infected individuals, and contaminated water sources contribute to higher prevalence rates in these regions.
Epidemiology: In some developing countries Giardia is present in 30% of the population. In the United States it is estimated that it is present in 3–7% of the population. Giardiasis is associated with impaired growth and development in children, particularly influencing a country's economic growth by affecting Disability Adjusted Life Year (DALY) rates.The number of reported cases in the United States in 2018 was 15,584. All states that classify giardiasis as a notifiable disease had cases of giardiasis. The states of Illinois, Kentucky, Mississippi, North Carolina, Oklahoma, Tennessee, Texas, and Vermont did not notify the Center for Disease Control regarding cases in 2018. The states with the highest number of cases in 2018 were California, New York, Florida, and Wisconsin. There are seasonal trends associated with giardiasis. July, August, and September are the months with the highest incidence of giardiasis in the United States.In the ECDC's (European Centre for Disease Prevention and Control) annual epidemiological report containing 2014 data, 17,278 confirmed giardiasis cases were reported by 23 of the 31 countries that are members of the EU/EEA. Germany reported the highest number at 4,011 cases. Following Germany, the UK reported 3,628 confirmed giardiasis cases. Together, this accounts for 44% of total reported cases.
Intractability: Giardiasis is generally not considered intractable. It is typically treatable with prescription medications such as metronidazole, tinidazole, or nitazoxanide. Proper medical treatment and good hygiene practices can effectively manage and resolve the infection in most cases.
Disease Severity: Giardiasis typically results in mild to moderate disease severity. In most cases, it presents with gastrointestinal symptoms such as diarrhea, bloating, and abdominal cramps. However, it can become more severe in individuals with weakened immune systems, leading to chronic infection and more serious health issues.
Healthcare Professionals: Disease Ontology ID - DOID:10718
Pathophysiology: The life cycle of Giardia consists of a cyst form and a trophozoite form. The cyst form is infectious and once it has found a host, transforms into the trophozoite form. This trophozoite attaches to the intestinal wall and replicates within the gut. As trophozoites continue along the gastrointestinal tract, they convert back to their cyst form which is then excreted with faeces. Ingestion of only a few of these cysts is needed to generate infection in another host.Infection with Giardia results in decreased expression of brush border enzymes, morphological changes to the microvillus, increased intestinal permeability, and programmed cell death of small intestinal epithelial cells. Both trophozoites and cysts are contained within the gastrointestinal tract and do not invade beyond it.The attachment of trophozoites causes villous flattening and inhibition of enzymes that break down disaccharide sugars in the intestines. Ultimately, the community of microorganisms that lives in the intestine may overgrow and may be the cause of further symptoms, though this idea has not been fully investigated. The alteration of the villi leads to an inability of nutrient and water absorption from the intestine, resulting in diarrhoea, one of the predominant symptoms. In the case of asymptomatic giardiasis, there can be malabsorption with or without histological changes to the small intestine. The degree to which malabsorption occurs in symptomatic and asymptomatic cases is highly varied.The species Giardia intestinalis uses enzymes that break down proteins to attack the villi of the brush border and appears to increase crypt cell proliferation and crypt length of crypt cells existing on the sides of the villi. On an immunological level, activated host T lymphocytes attack endothelial cells that have been injured in order to remove the cell. This occurs after the disruption of proteins that connect brush border endothelial cells to one another. The result is increased intestinal permeability.There appears to be a further increase in programmed enterocyte cell death by Giardia intestinalis, which further damages the intestinal barrier and increases permeability. There is significant upregulation of the programmed cell death cascade by the parasite, and, furthermore, substantial downregulation of the anti-apoptotic protein Bcl-2 and upregulation of the proapoptotic protein Bax. These connections suggest a role of caspase-dependent apoptosis in the pathogenesis of giardiasis.Giardia protects its own growth by reducing the formation of the gas nitric oxide by consuming all local arginine, which is the amino acid necessary to make nitric oxide. Arginine starvation is known to be a cause of programmed cell death, and local removal is a strong apoptotic agent.
Carrier Status: Carrier status for giardiasis refers to individuals who are infected with the Giardia parasite but do not exhibit any symptoms. These asymptomatic carriers can still shed cysts of the parasite in their feces, potentially spreading the infection to others through contaminated water, food, or surfaces.
Mechanism: Giardiasis is an intestinal infection caused by the protozoan parasite Giardia lamblia. Here’s a summary of its mechanism and molecular mechanisms:

**Mechanism:**
1. **Transmission:** Giardiasis is commonly transmitted through ingestion of cysts in contaminated water, food, or via the fecal-oral route.
2. **Excystation:** In the host's stomach, the acidic environment triggers the cysts to release the trophozoites (active form) in the small intestine.
3. **Attachment:** Trophozoites attach themselves to the epithelial cells of the small intestine using a ventral adhesive disc, disrupting normal absorption processes.
4. **Reproduction:** Trophozoites multiply by binary fission in the small intestine, leading to an increased number of parasites and further disruption of the intestinal lining.
5. **Encystation:** Some trophozoites encyst again in the lower small intestine, turning into the infectious cyst form that is excreted in feces, ready to infect a new host.

**Molecular Mechanisms:**
1. **Adhesion:** The ventral adhesive disc composed of cytoskeletal proteins allows the trophozoites to adhere tightly to the intestinal epithelium.
2. **Nutrient Uptake Interference:** Giardia can absorb nutrients directly from the lumen, competing with the host and leading to malabsorption and diarrhea.
3. **Barrier Disruption:** Giardia disrupts the tight junctions between epithelial cells using proteolytic enzymes, increasing intestinal permeability.
4. **Immune Evasion:** The parasite can modulate host immune responses through antigenic variation of its surface proteins (variant-specific surface proteins, VSPs), avoiding detection and clearance.
5. **Cellular Mechanisms:** Giardia trophozoites produce metabolic by-products like hydrogen and acetate, which further disrupt cellular functions and contribute to symptoms like bloating and gas.

Understanding these mechanisms helps in diagnosing, treating, and preventing giardiasis.
Treatment: Treatment is not always necessary as the infection usually resolves on its own. However, if the illness is acute or symptoms persist and medications are needed to treat it, a nitroimidazole medication is used such as metronidazole, tinidazole, secnidazole or ornidazole.The World Health Organisation and Infectious Disease Society of America recommend metronidazole as first line therapy. The US CDC lists metronidazole, tinidazole, and nitazoxanide as effective first-line therapies; of these three, only nitazoxanide and tinidazole are approved for the treatment of giardiasis by the US FDA. A meta-analysis published by the Cochrane Collaboration in 2012 found that compared to the standard of metronidazole, albendazole had equivalent efficacy while having fewer side effects, such as gastrointestinal or neurologic issues. Other meta-analyses have reached similar conclusions. Both medications need a five to ten day-long course; albendazole is taken once a day, while metronidazole needs to be taken three times a day. The evidence for comparing metronidazole to other alternatives such as mebendazole, tinidazole or nitazoxanide was felt to be of very low quality. While tinidazole has side effects and efficacy similar to those of metronidazole, it is administered with a single dose.Resistance has been seen clinically to both nitroimidazoles and albendazole, but not nitazoxanide, though nitazoxanide resistance has been induced in research laboratories. The exact mechanism of resistance to all of these medications is not well understood. In the case of nitroimidazole-resistant strains of Giardia, other drugs are available which have showed efficacy in treatment including quinacrine, nitazoxanide, bacitracin zinc, furazolidone and paromomycin. Mepacrine may also be used for refractory cases.Probiotics, when given in combination with the standard treatment, have been shown to assist with clearance of Giardia.During pregnancy, paromomycin is the preferred treatment drug because of its poor intestinal absorption, resulting in less exposure to the foetus. Alternatively, metronidazole can be used after the first trimester as there has been wide experience in its use for trichomonas in pregnancy.
Compassionate Use Treatment: Compassionate use treatment, off-label, and experimental treatments for giardiasis may include:

1. **Compassionate Use Treatment**: This typically refers to the use of experimental drugs or treatments for patients who are not responding to standard treatments and have no other options available. Specific details for giardiasis can vary and would typically involve close consultation with a healthcare provider and regulatory bodies.

2. **Off-Label Treatments**: Nitazoxanide is approved for giardiasis but is also used off-label for treating infections caused by other parasites. Tinidazole, though primarily listed for amoebiasis, is often used off-label for giardiasis, particularly when first-line treatments fail.

3. **Experimental Treatments**: Research is ongoing for new therapies, including novel antiparasitic medications and vaccines. No specific experimental treatments are currently standard, but clinical trials may offer new options.

Consulting a healthcare professional is vital for accessing the latest and most appropriate treatment options.
Lifestyle Recommendations: ### Lifestyle Recommendations for Giardiasis

1. **Hydration**: Drink plenty of fluids, such as water and oral rehydration solutions, to prevent dehydration, which can result from diarrhea.

2. **Hygiene**:
- Wash hands thoroughly with soap and water, especially before eating and after using the bathroom.
- Avoid consuming food or beverages prepared by someone who is infected.
- Avoid swimming in pools, lakes, or rivers if you have diarrhea; if you are not symptomatic, still avoid swallowing water when swimming.

3. **Diet**:
- Avoid dairy products and foods high in fat which can worsen symptoms.
- Eat easy-to-digest foods like bananas, rice, apple sauce, and toast (BRAT diet).

4. **Food and Water Safety**:
- Drink boiled or bottled water, especially when traveling to areas with poor sanitation.
- Avoid raw or undercooked foods and wash fruits and vegetables thoroughly.

5. **Preventative Measures**:
- Avoid contact with feces from infected persons or animals.
- Clean and disinfect surfaces that may be contaminated.

6. **Medication**: Follow the prescribed treatment regimen strictly to ensure full recovery and reduce the risk of transmission.

Adhering to these lifestyle recommendations could help manage symptoms and prevent the spread of giardiasis.
Medication: Giardiasis is typically treated with antiparasitic medications. The most commonly prescribed medications include:

- Metronidazole
- Tinidazole
- Nitazoxanide

These medications help eliminate the Giardia parasite from the digestive tract. It is important to follow the prescribed course of treatment and maintain good hydration to manage symptoms. Always consult with a healthcare provider for appropriate diagnosis and treatment.
Repurposable Drugs: Repurposable drugs for giardiasis include Metronidazole, Tinidazole, Nitazoxanide, Furazolidone, Paromomycin, and Albendazole.
Metabolites: For giardiasis, specific metabolites include:

1. **Glucose**: Giardiasis can affect glucose metabolism in the host and the Giardia parasite itself relies on glucose for energy via glycolysis.
2. **Arginine**: Giardia lamblia uses the arginine dihydrolase pathway to produce energy and metabolic intermediates.
3. **Short-chain fatty acids (SCFAs)**: The presence of giardiasis can alter the levels of SCFAs in the intestine, impacting gut microbial metabolism.

“Nan,” in this context, is not clear. If referring to nanoparticles, their role in giardiasis treatment or diagnosis is still under research, with potential applications in drug delivery and diagnostic imaging. If additional specific information is needed, please clarify "nan."
Nutraceuticals: There is limited scientific evidence on the use of nutraceuticals specifically for giardiasis. Some natural options, such as garlic, berberine, and probiotics, may offer supportive effects, but these should not replace conventional treatments like metronidazole or tinidazole. Consult a healthcare professional for personalized advice.
Peptides: Giardiasis is an infection caused by the protozoan parasite Giardia lamblia. Peptides are short chains of amino acids that can play various roles in the body, including serving as hormones, neurotransmitters, or antimicrobial agents. Research into peptides related to giardiasis involves understanding how the parasite interacts with the host's immune system and identifying peptide-based treatments or diagnostic markers.

"NAN" is not a recognized term in the context of giardiasis. If you intended "nanotechnology" or "nanoparticles," these are areas of ongoing research to develop advanced diagnostic tools or therapies. For instance, nanoparticles may be used to deliver drugs more effectively to target the parasite without harming the host's cells.