#Cryptosporidium spp. oocysts

[raptorsandpoultry]

Protist parasites in poultry

Eimeria spp.

The most famous and problematic internal parasites in poultry are Eimeria spp., which belong to the Coccidia order of protists, or protozoa. These organisms are single-celled and possess unique mechanisms that enable them to penetrate a host animal’s cells, which they must infect in order to survive and reproduce.

The 4 most commonly known species of Eimeria in poultry are E. acervulina, E. maxima, E. necatrix, and E. tenella. All infect the lining cells of the small intestines or ceca (paired fermenting organs). Resulting clinical disease is an enteritis (inflammation of the intestines) and diarrhea, which may or may not be accompanied by hemorrhage, or internal bleeding. E. tenella and E. necatrix cause the most severe disease, featuring hemorrhage, anemia (lack of red blood cells), and death at around 6 days post-infection. Although mortality rates are very high, chicks that do survive develop immunity to future coccidia infections. Severe infections with the other species will mainly cause weight loss and decreased egg production. 

Coccidiosis largely results from current intensive rearing practices on commercial poultry farms - however, more instances of the disease do not occur due to the widespread and continual use of preventative anticoccidial drugs in feed. Outbreaks can still occasionally occur when drug-resistant strains of Eimeria emerge. Vaccination against coccidiosis tends to be reserved for “replacement” hens on egg-layer farms.

Cryptosporidium spp.

Distant relatives of coccidia, there are many species of Cryptosporidium, 2 of which - C. meleagridis and C. baileyi - commonly cause disease in farmed chickens and turkeys of all ages. The former tends to infect the small intestine and ceca, resulting in mild diarrhea, while the latter causes more harmful respiratory infections. Clinical signs include depression, coughing, sneezing, and gurgling, but do not usually result in death. 

There are no specific drugs or vaccines available for prevention or treatment of cryptosporidiosis - supportive care with fluid therapy is recommended if diarrhea is severe. Strict, sanitary housing and handling practices are key to prevention, especially since oocysts (eggs) of Cryptosporidium spp. are resistant to most common disinfectants. Like Eimeria spp., diagnosis of cryptosporidiosis is confirmed by finding oocysts in microscopic examination of feces, or in the case of C. baileyi, nasal discharge.

Trichomonas gallinae

T. gallinae is found in chickens and turkeys, and is very common in pigeons. It infects the mouth, sinuses, throat, esophagus, crop, and proventriculus (the first component of the stomach in birds, which is usually followed by the gizzard). In pigeons, infection primarily occurs through direct oral transmission from parents to their offspring during the feeding of “crop milk”, or regurgitated crop contents. Early lesions are yellow to white areas that later become raised and necrotic “buttons” of dying tissue. “Wild” or feral pigeons are the usual source of infection.

Histomonas meleagridis

This “cosmopolitan” parasite infects the ceca and liver of virtually all gallinaceous fowl, including chicken, peafowl, guineafowl, pheasant, grouse, quail, and backyard turkeys in particular. Direct fecal-oral transmission is possible, but the more common route of infection is through the ingestion of the eggs of Heterakis gallinarum worms. H. meleagridis is ingested by the worm, penetrates its tissues, and then multiplies within the larval worms while they are still within their eggshells. These eggs are then ingested by earthworms, which are finally preyed upon by backyard birds, releasing H. meleagridis into their digestive tracts. The resulting disease is called blackhead, infectious enterohepatitis, or histomoniasis. Chickens generally do not present with any signs unless they are very young. Turkeys of all ages are affected, however, and the disease can kill young poults. The parasites kill liver cells, and two to three weeks later turkeys will look very sick, with ruffled feathers, drooping wings and tail feathers, and sometimes darkened skin around the head (hence “blackhead” disease). Foul-smelling, sulfur-coloured diarrhea is another characteristic sign of the disease.

Metronidazole, or “Flagyl” is a drug that is available for off-label use to treat histomoniasis, but is prohibited in birds raised for food production. Thus, control is generally aimed at preventative measures that restrict contact with infected soil (this also is why many people recommend that backyard chickens and turkeys should not be allowed to free-range over the same areas). Anthelminthics, or de-worming drugs, can also help by getting rid of Heterakis worms that harbour the parasites in the first place.

[parasite-bench]

Intestinal Sporozoans

Isospora belli

ingestion of oocysts in fecally contaminated food/water

human is definitive host

diagnosis by oocysts in stool specimens; modified kinyoun stain

tropical and subtropical areas

eosinophilia

Cryptosporidium spp.

ingestion of oocysts from food/water contaminated with animal feces, oral-anal, direct contact with infected individual or animal

zoonotic and non-zoonotic

swimming pools, water playgrounds, and other swimming venues; unpasteurized cider, juice, and milk; contact with animals; childcare settings; camps; and ill food handlers

opportunistic in AIDS patients

diagnosis by oocysts in stool specimens; modified kinyoun stain

GIPCR

Cyclospora cayentanensis

contaminated food/water

humans are only host

diagnosis by oocysts in wet mount of stool specimens; modified kinyoun stains

GIPCR

tropical and subtropical areas; outbreaks in spring and summer months

oocysts are not immediately infectious unlike coccidian sporozoans

[healthtimetaylor]

Anti-protozoal activity of extracts from chicory against Cryptosporidium parvum in cell culture.

PMID:  Sci Rep. 2019 Dec 31 ;9(1):20414. Epub 2019 Dec 31. PMID: 31892721 Abstract Title:  Anti-protozoal activity of extracts from chicory (Cichorium intybus) against Cryptosporidium parvum in cell culture. Abstract:  Cryptosporidium spp. are responsible for severe public health problems and livestock production losses. Treatment options are limited to only one drug available for human and bovine cryptosporidiosis, respectively, and both drugs exhibit only partial efficacy. Sesquiterpene lactones (SL) are plant bioactive compounds that function as a defence mechanism against herbivores. SL have demonstrated anti-parasitic properties against a range of parasitic taxa but knowledge about their anti-Cryptosporidium efficacy is limited. The effect of SL-rich leaf and root extracts from chicory (Cichorium intybus cv. Spadona) was investigated using human colon adenocarcinoma (HCT-8) cells infected with Cryptosporidium parvum. C. parvum oocysts were inoculated onto the cell monolayer and i) incubated for 4 hours with extracts (leaf and root extracts 300, 150, 75, 37.5, 18.75 and 9.375 μg/mL) in triplicates followed by incubation in bioactive free media (sporozoite invasion assays) or ii) incubated for 4 hours in bioactive free media followed by 48-hours incubation with extracts (growth inhibition assays). Extract toxicity on HCT-8 cells was assessed via water-soluble tetrazolium (WST)-1 assay prior to quantifying parasitic growth via immunofluorescence. Both extracts demonstrated dose-dependent inhibition in the growth inhibition assays (p = 

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