Isospora
Isosporiasis
Coccidiosis
Eimeriidae
Oocysts
Coccidia
Intestinal Diseases, Parasitic
Protozoan Infections
Feces
Parasitic Diseases, Animal
Re-descriptions of Isospora ameivae Carini, 1932 in the teiid lizard Ameiva ameiva and isospora hemidactyli Carini, 1936 in the gecko Hemidactylus mabouia, with particular reference to their endogenous stages. (1/46)
Redescriptions are given of the mature oocysts of Isospora ameivae Carini, 1932, from the teiid lizard Ameiva ameiva, and Isospora hemidactyli Carini,1936 from the gecko Hemidactylus mabouia, in north Brazil. The endogenous stages of the two parasites in the small intestine are described. Those of I. ameivae are intracytoplasmic, whereas those of I. hemidactyli are intranuclear. (+info)Enteric parasites and AIDS. (2/46)
OBJECTIVE: To report on the importance of intestinal parasites in patients with AIDS, showing relevant data in the medical literature, with special emphasis on epidemiology, diagnosis and treatment of enteroparasitosis, especially cryptosporidiosis, isosporiasis, microsporidiasis and strongyloidiasis. DESIGN: Narrative review. (+info)The fine structure of the endogenous stages of Isospora hemidactyli Carini, 1936 in the Gecko Hemidactylus mabouia from North Brazil. (3/46)
The ultrastructure is described of the meronts, microgamonts and young oocyst stages of Isospora hemidactyli of the gecko Hemidactylus mabouia from Belem, PA, north Brazil. The endogenous stages all develop in the nucleus of the gut epithelial cells. The nucleus remains intact up to the latest stages of the parasite's development, but degenerates by the time the oocyst appears. Merogonic division appears to be asynchronous, and some of the differentiated merozoites contained more than one nucleus. Microgamonts conform in structure with those of other eimeriids. Some of the type 2 wall-forming bodies disintegrate into smaller globules and ground substance of lower density. (+info)Differential effects of endoparasitism on the expression of carotenoid- and melanin-based ornamental coloration. (4/46)
The striking diversity of sexual dimorphisms in nature begs the question: Why are there so many signal types? One possibility is that ornamental traits convey different sets of information about the quality of the sender to the receiver. The colourful, pigmented feathers of male birds seem to meet the predictions of this hypothesis. Evidence suggests that carotenoid pigmentation reflects the nutritional condition of males during moult, whereas in many instances melanin pigmentation is a reliable indicator of social status. However, as of yet there have been no experimental tests to determine how these two ornament types respond to the same form of environmental stress. In this study, we tested the effect of endoparasitic infection by intestinal coccidians (Isospora sp.) on the expression of both carotenoid- and melanin-based ornamental coloration in captive male American goldfinches (Carduelis tristis). We found that the carotenoid-based plumage and bill coloration of parasitized males was less saturated than that developed by unparasitized males, but that the brightness and size of melanin-based black caps did not differ between the groups. These findings provide the most robust empirical support to date for the notion that carotenoid and melanin ornaments reveal different information to conspecifics. (+info)Phylogenetic position of a renal coccidium of the European green frogs, 'Isospora' lieberkuehni Labbe, 1894 (Apicomplexa: Sarcocystidae) and its taxonomic implications. (5/46)
'Isospora' lieberkuehni, an unusual isosporoid renal coccidium that parasitizes the European water frog was isolated from the edible frog, Rana kl. esculenta, in the Czech Republic. Sequencing of the small-subunit (SSU) rRNA gene showed that it belongs to the family Sarcocystidae, being closely related to a clade comprising members of the subfamily Toxoplasmatinae. The position within Sarcocystidae correlates with the mode of excystation via collapsible plates as postulated by previous authors. Phylogenetic, morphological and biological differences between 'Isospora' lieberkuehni and the other Stiedabody-lacking members of the genus Isospora justify separation of this coccidium on a generic level. Hyaloklossia Labbe, 1896 is the oldest available synonym and is herein re-erected. The original definition of the genus Hyaloklossia is emended based on recent observations. (+info)Case report: Nitazoxanide treatment failure in chronic isosporiasis. (6/46)
We report a 60-year-old immunocompetent patient with chronic biliary isosporiasis who failed to respond to orally administered cotrimoxazole prophylaxis and orally administered treatment with nitazoxanide, a 5-nitrothiazole benzamide compound. Severe malabsorption was regarded as responsible for the subtherapeutic levels of nitazoxanide in plasma and bile, resulting in treatment failure. Intravenously administered cotrimoxazole stopped the shedding of Isospora belli oocysts in bile within 5 days, excluding initially suspected resistance to cotrimoxazole. Patients with malabsorption and cholangitis due to Coccidia such as Isospora belli and Cryptosporidium spp. or due to protozoa that cause microsporidiasis seem to be predisposed to fail to respond to otherwise effective treatment. (+info)An outbreak of adenoviral infection in inland bearded dragons (Pogona vitticeps) coinfected with dependovirus and coccidial protozoa (Isospora sp.). (7/46)
Thirty of 200 (15%) hatchling inland bearded dragons were found dead after a short period (48 hours) of weakness and lethargy. The most common clinical signs were head tilt and circling. Six bearded dragons with neurological signs were euthanized, and postmortem examination revealed no gross abnormalities. Microscopically, severe, randomly distributed hepatocellular necrosis with large basophilic intranuclear inclusion bodies in numerous hepatocytes was noted. Small-intestinal enterocytes contained intracytoplasmic coccidial protozoa (Isospora sp.) and occasional enterocytes had basophilic intranuclear inclusion bodies. Transmission electron microscopy revealed both 80- and 20-nm-diameter viral particles, which were consistent with adenoviruses and dependoviruses, respectively. Adenoviral outbreaks in groups of animals are uncommon. An adverse synergistic effect of the coccidiosis with the adenoviral infection may have played a critical role in the high morbidity and mortality in this case. (+info)Comparison of autofluorescence and iodine staining for detection of Isospora belli in feces. (8/46)
To evaluate the sensitivity of autofluorescence for detection of Isospora oocysts, wet preparations of 192 stool samples from patients with chronic diarrhea were examined by fluorescence microscopy and by light microscopy after iodine staining used for routine screening for ova and parasites. Silicon-chambered glass coverslips were used for fluorescence microscopy. Isospora oocysts were detected in 46 iodine-stained concentrated stool samples; 91 samples were positive by autofluorescence. According to the maximum likelihood estimates, examination by fluorescence (95.7%; 95% confidence interval [CI], 85.2-99.5) was significantly more sensitive than iodine staining (48.4%; 95% CI, 37.7-59.1). Examination for autofluorescence is a simple, highly sensitive, inexpensive, and easily applicable method to detect Isospora spp. oocysts in feces. (+info)Isospora is a genus of protozoan parasites that belong to the phylum Apicomplexa. These parasites are the causative agents of coccidiosis, a type of gastrointestinal infection that primarily affects birds and mammals, including humans. The disease is characterized by watery diarrhea, abdominal pain, vomiting, and weight loss.
Isospora species have a complex life cycle that involves two hosts: an intermediate host, where the parasite reproduces asexually, and a definitive host, where the parasite undergoes sexual reproduction. The infectious stage of the parasite is called an oocyst, which is shed in the feces of the infected host and can survive in the environment for long periods. When ingested by another host, the oocyst releases sporozoites, which invade the intestinal cells and multiply, causing damage to the intestinal lining and leading to the symptoms of coccidiosis.
In humans, Isospora belli is the most common species that causes infection. It is typically transmitted through the fecal-oral route, either by ingesting contaminated food or water or by person-to-person contact. Immunocompromised individuals, such as those with HIV/AIDS, are at higher risk of developing severe and chronic infections with Isospora. Treatment usually involves the use of antiprotozoal drugs, such as trimethoprim-sulfamethoxazole.
Isosporiasis is a gastrointestinal infection caused by the protozoan parasite Isospora belli. It is characterized by watery diarrhea, abdominal cramps, nausea, and fever. The infection is typically spread through the fecal-oral route, often through contaminated food or water. Immunocompromised individuals, such as those with HIV/AIDS, are at an increased risk for severe and chronic infections. Diagnosis is made through identification of the parasite's oocysts in stool samples. Treatment typically involves the use of antiprotozoal medications such as trimethoprim-sulfamethoxazole (TMP-SMX).
Coccidiosis is a parasitic infection caused by protozoa of the Eimeria genus, which typically affects the intestinal tract of animals, including humans. The infection occurs when a person or animal ingests oocysts (the infective stage of the parasite) through contaminated food, water, or direct contact with infected feces.
In humans, coccidiosis is most commonly found in children living in poor sanitary conditions and in individuals with weakened immune systems, such as those with HIV/AIDS or organ transplant recipients on immunosuppressive therapy. The infection can cause watery diarrhea, abdominal pain, nausea, vomiting, and fever. In severe cases, it may lead to dehydration, weight loss, and even death in individuals with compromised immune systems.
In animals, particularly in poultry, swine, and ruminants, coccidiosis can cause significant economic losses due to decreased growth rates, poor feed conversion, and increased mortality. Preventive measures include improving sanitation, reducing overcrowding, and administering anticoccidial drugs or vaccines.
Eimeriidae is a family of protozoan parasites that includes several genera of coccidia, which are intracellular parasites that infect and replicate within the cells of various animals, including humans. The most well-known genus in this family is Eimeria, which contains many species that can cause coccidiosis in a variety of animals, including poultry, cattle, sheep, goats, and rabbits.
Coccidiosis is a disease that affects the intestinal tract and can lead to diarrhea, weight loss, and even death in severe cases. The parasites are typically transmitted through fecal-oral contact, either by ingesting contaminated food or water or by direct contact with infected animals.
Eimeriidae species have complex life cycles that involve several stages of development within the host's body. After ingestion, the parasites infect and replicate within intestinal epithelial cells, eventually leading to the release of new parasites into the environment through feces. These new parasites can then infect other hosts and continue the life cycle.
Prevention and control measures for coccidiosis typically involve good hygiene practices, such as cleaning and disinfecting contaminated surfaces and equipment, as well as the use of anticoccidial drugs to prevent or treat infections. Vaccination is also available for some species of Eimeria, although it may not be effective against all strains.
An oocyst is a thick-walled, environmentally resistant spore-like structure produced by some protozoan parasites, such as Cryptosporidium and Cyclospora, during their life cycle. These oocysts can survive for long periods in the environment and can infect a host when ingested, leading to infection and disease. The term "oocyst" is specific to certain groups of protozoan parasites and should not be confused with other types of spores produced by fungi or bacteria.
Coccidia are a group of single-celled, microscopic parasites that belong to the phylum Apicomplexa. They are obligate intracellular parasites, which means they need to infect and live inside the cells of a host organism to survive and multiply. Coccidia are primarily found in animals, including mammals, birds, reptiles, and fish, but some species can also infect humans.
Coccidia are known to cause coccidiosis, a common intestinal disease that affects various animal species, including poultry, cattle, swine, sheep, goats, and pets such as cats and dogs. The disease is characterized by diarrhea, weight loss, dehydration, and sometimes death, particularly in young animals.
In humans, coccidia infection is usually caused by the species Cryptosporidium and Cyclospora. These parasites can infect the small intestine and cause watery diarrhea, stomach cramps, nausea, vomiting, fever, and weight loss. In immunocompromised individuals, such as those with HIV/AIDS or those undergoing chemotherapy, coccidia infections can be severe and life-threatening.
Coccidia are typically transmitted through the fecal-oral route, either by ingesting contaminated food or water or by direct contact with infected animals or their feces. Prevention measures include good hygiene practices, such as washing hands thoroughly after handling animals or using the restroom, avoiding drinking untreated water from sources that may be contaminated with animal feces, and practicing safe food handling and preparation.
Parasitic intestinal diseases are disorders caused by microscopic parasites that invade the gastrointestinal tract, specifically the small intestine. These parasites include protozoa (single-celled organisms) and helminths (parasitic worms). The most common protozoan parasites that cause intestinal disease are Giardia lamblia, Cryptosporidium parvum, and Entamoeba histolytica. Common helminthic parasites include roundworms (Ascaris lumbricoides), tapeworms (Taenia saginata and Taenia solium), hookworms (Ancylostoma duodenale and Necator americanus), and pinworms (Enterobius vermicularis).
Parasitic intestinal diseases can cause a variety of symptoms, including diarrhea, abdominal pain, bloating, nausea, vomiting, fatigue, and weight loss. The severity and duration of the symptoms depend on the type of parasite, the number of organisms present, and the immune status of the host.
Transmission of these parasites can occur through various routes, including contaminated food and water, person-to-person contact, and contact with contaminated soil or feces. Preventive measures include practicing good hygiene, washing hands thoroughly after using the toilet and before handling food, cooking food thoroughly, and avoiding consumption of raw or undercooked meat, poultry, or seafood.
Treatment of parasitic intestinal diseases typically involves the use of antiparasitic medications that target the specific parasite causing the infection. In some cases, supportive care such as fluid replacement and symptom management may also be necessary.
Protozoan infections are diseases caused by microscopic, single-celled organisms known as protozoa. These parasites can enter the human body through contaminated food, water, or contact with an infected person or animal. Once inside the body, they can multiply and cause a range of symptoms depending on the type of protozoan and where it infects in the body. Some common protozoan infections include malaria, giardiasis, amoebiasis, and toxoplasmosis. Symptoms can vary widely but may include diarrhea, abdominal pain, fever, fatigue, and skin rashes. Treatment typically involves the use of antiprotozoal medications to kill the parasites and alleviate symptoms.
Feces are the solid or semisolid remains of food that could not be digested or absorbed in the small intestine, along with bacteria and other waste products. After being stored in the colon, feces are eliminated from the body through the rectum and anus during defecation. Feces can vary in color, consistency, and odor depending on a person's diet, health status, and other factors.
Parasitic diseases, animal, refer to conditions in animals that are caused by parasites, which are organisms that live on or inside a host and derive benefits from the host at its expense. Parasites can be classified into different groups such as protozoa, helminths (worms), and arthropods (e.g., ticks, fleas).
Parasitic diseases in animals can cause a wide range of clinical signs depending on the type of parasite, the animal species affected, and the location and extent of infection. Some common examples of parasitic diseases in animals include:
* Heartworm disease in dogs and cats caused by Dirofilaria immitis
* Coccidiosis in various animals caused by different species of Eimeria
* Toxoplasmosis in cats and other animals caused by Toxoplasma gondii
* Giardiasis in many animal species caused by Giardia spp.
* Lungworm disease in dogs and cats caused by Angiostrongylus vasorum or Aelurostrongylus abstrusus
* Tapeworm infection in dogs, cats, and other animals caused by different species of Taenia or Dipylidium caninum
Prevention and control of parasitic diseases in animals typically involve a combination of strategies such as regular veterinary care, appropriate use of medications, environmental management, and good hygiene practices.
Cyclospora is a single-celled parasite that causes an intestinal infection known as cyclosporiasis. The parasite is primarily transmitted through contaminated food or water. When ingested, Cyclospora infects the small intestine and can cause symptoms such as diarrhea, stomach cramps, bloating, nausea, and fatigue. In some cases, the infection may be asymptomatic. The treatment for cyclosporiasis typically involves antibiotics such as trimethoprim-sulfamethoxazole (Bactrim, Septra). It is important to note that Cyclospora should not be confused with other similar parasites like Cryptosporidium or Giardia.
Isospora
Isospora sylvianthina
Isospora ashmoonensis
Isospora sylviae
Isospora hammondi
Isospora cardellinae
Cystoisospora belli
Eurasian blackcap
Eimeriidae
Red warbler
Grey currawong
List of parasites of the marsh rice rat
Red wattlebird
Australian raven
Eimeria kinsellai
Oryzomys
Eimeria palustris
Oryzomys couesi
Jára Cimrman
Grey wagtail
Eimeria couesii
Cyclospora
Red-vented bulbul
Eosinophilia
Cooper's hawk
Sarcocystis
Cystoisospora canis
Coccidiosis
Ziehl-Neelsen stain
Apicomplexan life cycle
Isospora - Wikipedia
Taxonomy browser (Isospora orlovi)
Isospora jacobfrenkeli | Atlas of Living Australia
Isospora (Isospora) - Mede
Cryptosporidium/Isospora Identification Test Information
ASTMH - (old) Zaiman Slide Library
BAM Chapter 25: Investigation of Food Implicated in Illness | FDA
CDC - Parasites
PDF) The ocurrence of dengue and weather changes in Brazil: A systematic review
CAMEL COCCIDIOSIS CAUSED BY ISOSPORA ORLOVI IN THE UNITED ARAB EMIRATES | Emirates Journal of Food and Agriculture
Intestinal Protozoal Diseases: Background, Pathophysiology, Etiology
Veterinary Sciences | Free Full-Text | Endoparasites of Selected Native Non-Domesticated Mammals in the Neotropics (New World...
Une cause rare de diarrhée: la coccidiose à Isospora belli<...
Detection of cryptosporidium species, Isospora species Nad cyclospora species in HIV/AIDS positive patients with diarrhoea in a...
Selected Disorders of the Pediatric Canine and Feline Patient | IVIS
Publication : USDA ARS
ASTMH - (old) Zaiman Slide Library
Citations - OJVM - Scientific Research Publishing
SciELO - Brazil - Frequency of parasites and Salmonella infection in captive maned-wolf, Chrysocyon brachyurus, kept in Zoos...
Advanced Search Results - Public Health Image Library(PHIL)
Taking stock: a review of the known parasites of the sleepy lizard, Tiliqua rugosa (Gray, 1825), a common lizard endemic to...
Zootaxa; Protozoa
Jens Peter Nielsen - Resultat
Specimens Associated with Outbreaks of Gastroenteritis
Common Internal Parasites of Swine | MU Extension
Cryptosporidium3
- Cryptosporidium species and Isospora species oocysts were detected using modified acid fast stain and rapid saffranin method. (journalcra.com)
- Both modified acid fast stain and rapid saffranin method are useful in demonstrating oocysts of Cryptosporidium species and Isospora species. (journalcra.com)
- Besides these, prevalence of Toxoplasma/Hammondia oocyst was 88%, Isospora oocyst 80% and Cryptosporidium oocyst 4% (ZN- staining). (ajol.info)
Belli2
- Limbos, P & Fain, A 1967, ' Une cause rare de diarrhée: la coccidiose à Isospora belli ', Acta Gastro-Enterologica Belgica , vol. 30, pp. 531-540. (itg.be)
- Cystoisosporiasis Cystoisosporiasis is infection with the protozoan Cystoisospora belli (previously known as Isospora belli ). (merckmanuals.com)
Giardia1
- Isospora, Giardia, Toxoplasma) organisms. (snapcats.org)
Cystoisospora2
- In 2005, all former Isospora species that infect mammalian hosts were reclassified as members of the genus Cystoisospora, a member of the Sarcocystidae family. (wikipedia.org)
- This test is recommended for the examination of stool for the presence of Cyclospora or Isospora (Cystoisospora) by modified acid-fast stain in outbreak settings only. (nphl.org)
Species3
- For instance, the house sparrow has 12 species of Isospora. (wikipedia.org)
- Isospora species oocyst (11.25%) was detected following formalin ether concentration technique. (journalcra.com)
- The species determined and their prevalence rates were as follows: Eimeria bovis(34%), E.auburnensis(27%), E.zeuernii(26%), E.ellipsoiDalıs (14%), E.canadensis (12%), E.cylindrica (7.9%), E.supspherica (7.2%), E.alabamensis (4.9%), E.bukidnonensis (2.2%), E.brasiliensis (0.8%) and Isospora sp. (tubitak.gov.tr)
Infection1
- Even though internal parasites are commonly associated with pasture and dry lot husbandry, some parasites such as Isospora (neonatal infection) may be present in total confinement. (missouri.edu)
Moineau1
- Les Isospora du Moineau. (wikipedia.org)
Diarrhea1
- A team of professors and graduate and undergraduate students made this discovery while investigating intestinal parasites such as isospora, which causes acute, non-bloody diarrhea in hosts, and the canary pox, which manifests in lesions of the skin and may eventually lead to the loss of digits. (statepress.com)
Baccam1
- Isospora frenkeli Grulet, Landau & Baccam, 1982 synonym nom. (ala.org.au)
Eimeria1
- Coccidiosis is caused by Eimeria and Isospora. (vedantu.com)
Genus1
- Isospora is a genus of internal parasites in the subclass Coccidia. (wikipedia.org)
Bacteria1
- Stained buffy coat smears are recommended to detect bacteria, spirochetes, and Leucocytozoon , Trypanosoma , or Isospora infections. (merckvetmanual.com)
Cyclospora3
- A new trichromic safranin stain for the detection of Cryptosporidium parvum, Cyclospora cayetanensis, species of Microsporidia and Isospora belli in fecal material]. (nih.gov)
- All the opportunistic parasites including Cryptosporidium parvum , Cyclospora cayetanensis , Isospora belli and Microsporidium spp . (biomedcentral.com)
- Opportunistic parasites such as Cryptosporidium parvum , Cyclospora cayetanensis , Isospora belli , and Microsporidia spp . (biomedcentral.com)
Microsporidia1
- Cryptosporidium parvum and Isospora belli) and microsporidia (particularly Enterocytozoon bieneusi, causing intestinal microsporidiosis). (nih.gov)
Cryptosporidium parvum and Isospora2
- Cryptosporidium parvum and Isospora belli oocysts stained with carbol-fuchsin, as in a modified Ziehl Neelsen technique, fluoresce bright red under green light (546nm). (nih.gov)
- Comparison between the modified Ziehl-Neelsen and Acid-Fast-Trichrome methods for fecal screening of Cryptosporidium parvum and Isospora belli]. (nih.gov)
Coccidia3
- Isospora is a genus of internal parasites in the subclass Coccidia. (wikipedia.org)
- In this dissertation the circadian rhythmics of the excretion of Isospora lacazei ( one to the order of coccidia belonging parasitic protozoan in song-birds), was examined in dependency on the chronobiological behaviour of house sparrows (Passer domesticus L) under modification of light conditions as well as the endogenous level of melatonin, which is produced in the pineal gland of the birds. (tum.de)
- The most common species of Coccidia in dogs are called Isospora Canis. (fidosavvy.com)
Oocysts5
- Cryptosporidium and Isospora oocysts are also autofluorescent, appearing violet under u.v. light (365 nm), and green under violet (405 nm) and blue-violet light (436 nm). (nih.gov)
- Sporulation, Morphology and Resistance of the Oocysts of Isospora urolonchae sp. (ntnu.edu.tw)
- Shedding of oocysts in piglets experimentally infected with Isospora suis. (mysciencework.com)
- Forty-seven piglets were inoculated with doses of 100 to 50,000 sporulated oocysts of Isospora suis. (mysciencework.com)
- Recently, oocysts of an Isospora -like species were found in the kidney and urine of Eptesicus fuscus (Vespertilionidae), but until a detailed description and a photosyntype or line drawing are available, this organism also must be considered a species inquirendae . (unl.edu)
Suis2
- Antisera made in rabbits to Isospora suis, Toxoplasma gondii, Hammondia hammondi, Sarcocystis neurona, Neospora caninum, and Caryospora bigenetica were tested against I. belli tissue cysts in the avidin-biotin peroxidase complex (ABC) immunohistological test. (vt.edu)
- The causative agent of the disease is the parasitic protozoan Isospora suis, which belongs to the river. (ramip.ink)
Belli infection2
- 18. [Isospora belli infection in a patient with adult T-cell leukemia]. (nih.gov)
- In the United States, Isospora belli infection occurs primarily in patients with AIDS but is still quite rare in this population, accounting for = 0.2% of AIDS-defining illnesses. (antiinfectivemeds.com)
Species that infect1
- The genera Eimeria (sporulated oocyst contains four sporocysts) and Isospora (sporulated oocyst contains two sporocysts) contain many species that infect a wide variety of birds, mammals and reptiles, but almost all are species host-specific. (merckvetmanual.com)
Infection2
- In cats, dogs, and horses, infection is mainly from Isospora spp, and clinical signs are less common and usually less severe than with Eimeria spp. (merckvetmanual.com)
- Isospora infection is endemic in several tropical and subtropical climates in areas of South America, Africa, and southwest Asia. (antiinfectivemeds.com)
Felis1
- Enteric multiplication of Isospora felis by endodyogeny. (roundtaiwanround.com)
House sparrow1
- For instance, the house sparrow has 12 species of Isospora. (wikipedia.org)
Fecal1
- We found in a previously run fecal float that our case study animal was infected with Isospora, and thus that's what I suspect is stained in this image. (microbestiary.org)
ORGANISMS1
- However, other parasitic organisms will also stain red, including members of Isospora. (microbestiary.org)
Humans1
- Relapse is common in immunocompetent and immunosuppressed humans infected with Isospora belli and is believed to be associated with the presence of extraintestinal stages. (vt.edu)
Case1
- this is not the case with Isospora. (nih.gov)