Toxoplasmosis (Toxoplasmosis) was discovered by French scholars in 1980 in the spleen monocytes of the Gangdi comb-toed rat, and taxonomically belongs to the protigeny realm - apical compound gate - coccidiosis - coccidioides - Meatsporids - Toxoplasmosis genus, the body is bow-shaped, the full name of the toxoplasma gondii . Toxoplasma gondii is an opportunistic protozoa, and toxoplasmosis infection usually does not show significant clinical symptoms in the case of normal immune function.
The life history of Toxoplasma gondii is more complex, the whole process needs to go through two types of hosts, intermediate host and terminal host, and the form of the worm body in the host is also very diverse, including fast breeders with strong infectious ability, slow growth and poor infection ability of brady protozoa, and egg sacs.
Intermediate host
In the intermediate host (human, dog, cat, rat and other thermostatic animals), Toxoplasma gondii will complete the extraintestinal development process, through the blood or lymphatic circulation into the tissues and organs (brain, eyes, lungs, liver, lymph, muscles, etc.) intracellular development and proliferation, resulting in damage to the corresponding organ tissues, the process will not be excreted through feces egg sacs.
End-of-host
In the terminal host (only cats), Toxoplasma gondii completes the development of the enteral phase. The colonization of the worm develops and proliferates in the intestinal epithelial cells to form an oocyst, which destroys the epithelial cells and returns to the intestinal lumen, and the oocyst is excreted with the feces of the cat. The oocysts that enter the environment develop into infective mature oocysts after 2-4 days, posing a threat to other susceptible animals.
The process from colonization to the release of the egg sac takes about 7-20 days, depending on the cat. As the only terminal host, cats produce antibodies during infection, which no longer excrete outwards after antibodies are produced.
Intermediate or terminal hosts consume food containing infected worm bodies (including tachyparents, bradys, and mature egg sacs), including improperly handled meat, dairy products, egg products, and drinking water.
Studies have shown that in a very small probability, Toxoplasma can be infected through the mouth, nose, eye conjunctiva or broken skin and mucous membranes; flies, cockroaches, earthworms, etc. can be used as a medium for the transmission of Toxoplasma gondii oocysts; arthropods carrying egg sacs also have certain transmission significance.
The onset of disease after infection with Toxoplasma gondii depends on factors such as strain virulence, the number of infections, the route of infection, and the immunity of the host. Cats have poor sensitivity to Toxoplasma gondii, with only a few clinical symptoms and very limited damage to the body.
Pathogenesis conditions
The strains infected by the host are highly virulent and fail to generate sufficient immunity.
Host immune function is weak, and the toxoplasmosis bradyle in the body may become a metabolic and rapidly proliferative tachygos.
Non-morbid condition (most cases)
The strain is weakly virulent, and the host quickly develops immunity, resulting in the reproduction of toxoplasma gondii is hindered.
The host is immune, and the toxoplasmosis hastis in the body transforms into slowly metabolized and multiplied brady progeny.
Cats should be tested for Toxoplasma gondii when:
1. There are members of the family who are trying to conceive or have poor immunity;
2. Physical health check after rescue and adoption of cats;
3. Cats show symptoms of suspected toxoplasmosis.
Toxoplasma gondii detection methods are diverse, considering "whether the cat itself is infected with Toxoplasma gondii" and "whether the cat has the risk of transmitting Toxoplasma gondii to other animals or people", the clinical commonly used fecal egg detection and serum antibody detection for comprehensive judgment.
Stool eggs test positive
It indicates that the cat is infected with Toxoplasma gondii and is in the worm elimination stage, at which time the serological antibody test is performed, and the antibody must be positive. If clinical symptoms appear, they can be relieved by medication, or if there are no clinical symptoms, only the growth of the worm needs to be suppressed.
Fecal eggs tested negative
It can only mean that the cat is not in the worm removal period at present, and there is no harm to the environment. If you want to determine if a cat is infected with Toxoplasma gondii, you also need to test for serum antibodies IgG and IgM.
1. Both IgG and IgM antibodies are negative: there is currently no toxoplasma gondii infection and no treatment is required.
2. IgG antibody is positive and low potency, IgM antibody is negative: toxoplasma have been infected, but at this stage will not cause damage to the body, no intervention is required.
3. Both IgG and IgM antibodies are positive and have high potency: it is in the active period of Toxoplasma toxoplasma infection, and it is necessary to use medication to inhibit its growth to avoid further harm to the cat.
Based on the results of the examination and combined with the physical condition and family situation of the cat, personalized treatment and care plan are carried out for cases with positive test results.
In addition to the above drugs against Toxoplasma gondii, cats can also be given drugs that regulate immune function such as recombinant IFN-γ or LAK cells.
Toxoplasma gondii infection in immunocompetent cats generally has a good prognosis; feline infections with immunodeficiency (such as congenital or acquired immunodeficiency) may have serious clinical manifestations and should be treated aggressively in a timely manner, and the prognosis should be cautious.
Cats are both intermediate and terminal hosts for Toxoplasma gondii, so prevention needs to be considered both with the cat's own prevention and the prevention of people living together or other susceptible animals such as dogs.
Prevention of foodborne infections
Cooking method
a. Meat cubes (all meat except poultry): After the meat pieces are cooked at a minimum temperature of 145 °F (63 °C), it takes 3 minutes to wake up the meat (rest) time before cutting or eating.
b. Minced meat (all meat except poultry): Cook to a minimum of 160 °F (71 °C), no time to wake up.
c. Poultry: Cook to a minimum of 165°F (74°C), if it is a piece of meat, after reaching this temperature, it takes 3 minutes to wake up the meat (rest) time before cutting or eating.
Prepare before cooking
a. Freezing meat for several days before cooking (sub-zero temperatures) can greatly reduce the risk of infection.
b. After contact with raw meat, seafood or unwashed vegetables and fruits, thoroughly wash utensils such as cutting boards, dinner plates and hands with soap and warm water.
In general, toxoplasmosis can be killed when cooking meat at an internal temperature greater than 67 °C (152.6 °F), and is not recommended because microwaves cannot guarantee completely uniform heating. Household refrigerators can also kill toxoplasmosis by freezing meat at -12°C for more than 24 hours.
Prevent environmental infections
1. Do not drink untreated raw water/tap water directly;
2. Wear gloves when exposed to outside soil, sand or cat litter pots, and wash your hands with soap and warm water after contact;
3. Inform children of the importance of handwashing;
4. Feed the cat finished dry food, wet food, or fully cooked/frozen homemade food, avoid direct feeding raw meat or semi-cooked meat;
5. For cats with confirmed infection or suspected to be infected with Toxoplasma gondii, the cat litter should be cleaned and replaced every day to prevent the egg sacs in the sand basin from becoming infectious oocysts.
If you have a pregnant woman or an immunosuppressed person at home
1. Avoid cleaning up the replacement cat litter yourself, and if you can't avoid it, wear disposable gloves when handling, and wash your hands with soap and warm water after handling.
2. Cats are raised completely indoors, avoiding possible intermediate hosts or shelterhopper hosts such as rats and earthworms.
3. Do not adopt or contact stray cats (especially kittens) with unknown infection, and do not raise new cats during pregnancy.
Whether for cats, humans or other animals, foodborne infection is the main route of toxoplasmosis infection, and daily attention should be paid to food hygiene. The probability of infection between humans or other animals interacting with cats is extremely low, if the cat itself is not infected with Toxoplasma gondii it is even more impossible to talk about, develop good hygiene habits, prevent diseases from entering the mouth, this is the best way to avoid Toxoplasma gondii infection!
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