Toxocariasis in Vietnam: What are the symptoms of infection? What is the source of the disease?
Causes and modes of transmission of toxocariasis in dogs/cats in Vietnam?
Pursuant to Section 1 of the Guidelines for diagnosis, treatment and prevention of toxocariasis in dogs/cats promulgated under Decision 1385/QD-BYT in 2022, it stipulates: "Canine/cat ascariasis is a parasitic disease Transmission from animals to humans is caused by Toxocara canis (Toxocara canis) or Cat roundworm (Toxocara cati). transferred in the skin to the severe form in organs such as the lungs, eyes, liver and nervous system of humans.
- Agent: Roundworm larvae in Vietnam dogs/cats (Toxocara canis/ Toxocara cati)
- Disease source: The main source or reservoir is dogs and cats infected with Toxocara spp worms, especially puppies are the reservoir of the highest risk for humans. In addition, some other animals (chickens, ducks, buffaloes, cows, sheep, rabbits) may carry the disease at a lower rate.
- Mode of transmission:
+ People who eat food and drinking water contaminated with dog/cat eggs.
+ People who eat offal or raw/undercooked meat of a host of pathogens such as chickens, ducks, buffaloes, cows, sheep, rabbits.
The disease is not transmitted directly from person to person.
- Susceptibility and immunity: People of both sexes can be infected and are susceptible to re-infection when living in an environment with endemic disease.
Toxocariasis in Vietnam: What are the symptoms of infection? What is the source of the disease?
Symptoms appear in roundworm larvae in Vietnam dogs/cats
Pursuant to Sections 2 and 3 of the Guidelines for diagnosis, treatment and prevention of ascariasis in Vietnam dogs/cats promulgated together with Decision 1385/QD-BYT in 2022, stipulating the symptoms appearing in larval disease Roundworms in Vietnam dogs/cats are as follows:
Clinical symptoms
- Common form: Symptoms are not too overwhelming, can be seen as
+ Itching, rash;
+ Headache;
+ Abdominal pain;
+ Cough;
+ Sleep disturbances;
+ Change behavior.
- The larval form moves in the eye: The ophthalmic form is uncommon, usually in one eye. Symptoms include:
+ Decreased vision;
+ Granuloma: posterior polar granuloma, peripheral granuloma;
endophthalmitis,
+ Damage to the retina, conjunctivitis, uveitis
Complete loss of vision.
- Larvae move internal organs
The larvae can migrate to various organs such as the heart, lungs and liver. Visceral form is more common in children under 7 years of age. The clinical symptoms are quite diverse depending on the number and location of the affected organs, the most common are:
+ Chronic abdominal pain, hepatomegaly, diarrhea, vomiting;
+ Bronchial asthma: Wheezing, dry cough, difficulty breathing;
+ Chest tightness;
+ Fever, headache, fatigue, weight loss;
+ Itching, rash.
- The larval body moves to the nervous system
This is a dangerous disease compared to other forms. Symptoms are not specific, the degree of manifestation depends on the location of the lesion in the nervous system such as:
+ Fever;
+ Headache;
+ Convulsions.
Subclinical
- Test
+ ELISA: Detects IgG antibodies against secreted antigens of Toxocara spp. in serum or intraocular fluid.
+ Complete blood count: Blood eosinophils increased > 7% (or > 500 cells/µl blood).
+ Erythrocyte sedimentation test: increased
+ CRP (C Reaction Protein): increase
+ Quantitative IgE test: increase
+ Stool test: look for other parasites to diagnose and rule out.
+ Biopsy: Determine histopathology of lesions infected with canine/cat ascariasis or identify larvae, often with eosinophilic infiltrates.
+ Molecular biology: Detecting specific gene segments of dog/cat ascaris larvae in biopsies.
- Image analysation
+ Chest X-ray: There are pictures of lung parenchyma damage, lung infiltrates.
+ Computed tomography (CT scanner): There is a density change image corresponding to the lesion area.
+ MRI scan of suspected lesions: detect signal changes corresponding to damaged areas.
+ Abdominal ultrasound, superficial transducer ultrasound: Detecting damage to intra-abdominal viscera or subcutaneous soft tissue. Visceral lesions in the form of nodules < 3cm, hypoechoic, heterogeneous, may have hyperechoic dots without internal shadow, lesions are fairly regular, well demarcated, without angiogenesis, with thin fibrous she around. Under the skin are infiltrative lesions, which can be localized depending on the stage.
+ Ophthalmoscopy: Signs of retinal fibrosis, "spin" marks, can see the image of larvae at the bottom of the eye.
Guidelines for diagnosis of roundworm larvae in Vietnam dogs/cats?
Pursuant to Section 4, Guidelines for the diagnosis, treatment and prevention of roundworm larvae in Vietnam dogs/cats promulgated together with Decision 1385/QD-BYT in 2022 stipulating the diagnosis of ascariasis in Vietnam dogs/cats as follows:
- Suspected case
A case with an epidemiological history of exposure to dogs/cats or risk factors and with the following symptoms:
+ Itching, rash;
+ Headache, abdominal pain, indigestion;
+ Aching pain, numbness;
+ Fever, wheezing;
+ May be accompanied by one or more of the following symptoms: Hepatomegaly, pneumonia, chronic abdominal pain, focal neurological disorders, eye damage, vision loss, retinal damage.
- Cases of confirmed disease
A case of suspected disease and having one of the following tests:
+ Found larvae of dog/cat roundworm.
+ Detection of specific gene segments of larvae by molecular biology.
+ Identify antibodies against toxocariasis in dogs/cats by ELISA.
+ Eosinophilia increased or
+ There is a suspicious lesion on imaging.
- Differential diagnosis
+ Atopic dermatitis;
+ Contact dermatitis;
+ Larval disease moving under the skin caused by larvae of hookworms/beaks, strongyloides;
+ Large liver fluke;
+ Larvae of swine fluke;
Infection with other intestinal roundworms.
This disease has many potential dangers to your health, so everyone must be very careful. When symptoms are detected, seek medical attention immediately for the best treatment.
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