| Table 1 |
Toxocara canis |
Dirofilaria immitis |
Fasciola hepatica |
Haemonchus contortus |
| Route(s) of entry to the host |
1. Ingestion of infective eggs
2. Ingestion of mouse hosts (paratenic)
3. Transplacental migration of L2s to fetal liver
4. Transmammary transmission of L3s to nursing pups |
1. Injection of L3s by blood-feeding female
mosquitos (intermediate hosts) |
1. Ingestion of metacercariae |
1. Ingestion of infective larvae |
| Predilection site |
Small intestine |
Right ventricle and pulmonary arteries |
Bile ducts of the liver |
Abomasum |
| Route to the predilection site |
Direct development in the small intestine after ingestion
of paratenic hosts and L3s from the mammary gland. Otherwise by tracheal
migration. |
Migration through the body and vascular
system |
Migration from the small intestine across the peritoneal
cavity to the liver |
Direct development in the abomasum after
ingestion |
| Route of exit from the host |
In the feces of the host |
In the blood meal taken by a mosquito feeding on the host. |
In the feces of the host |
In the feces of the host |
| Life cycle stage(s) entering the
host |
Egg, L2 or L3 depending on the route of
transmission |
L3 |
Encysted metacercaria |
Ensheathed L3 |
| Stage leaving the host
(diagnostic stage) |
Egg |
Microfilaria |
Egg |
Egg |
