Cycle:

It has an indirect life cycle and requires an arthropod intermediate host, since the eggs—which are laid and excreted along with feces—are ingested by intermediate hosts such as grasshoppers, crickets, locusts, cockroaches, etc.

The eggs, which once passed with the feces hatch, and are ingested by intermediate hosts that are aquatic crustaceans, Daphnia pulex and Gammarus pulex. The larvae hatch from the eggs and develop in the body cavity of the crustacean to the stage that is infectious.

Sixteen to twenty-four hours after infection, third-stage larvae are found deep within the mucosa of the main glands of the proventriculus, with no evidence of pathological changes at this stage.

Five days after infection, it causes dilation of the membrane of the gland and are larvae of the fourth stage, which measure 1.65 mm in length.

By day 10, marked sexual dimorphism is evident; in some glands, both males and females are present, but in others only females are seen; males are present in the mucous membrane.

By the twelfth day, the young females have grown considerably in size, and by the eighteenth day, only adult females remain in the basal glands.

In backyard poultry, the incidence can reach 30% (Moreno, 1989).

Etiology:

Tetrameres americana is a parasite that exhibits marked sexual dimorphism; the male measures 5–5.5 mm in length and is white in color, while the female is round in shape with longitudinal grooves, measures 3.5–4.5 mm in length by 3 mm in width, and is red in color (Moreno, 1989).

Clinical signs:

Diarrhea, anemia, and wasting due to the suction of blood and sadness. As in the majority of cases, the number of parasites is reduced, the signs do not manifest. In severe cases, the migration of the parasites youth glands paraventriculares causes a marked irritation and inflammation, that can cause the death of birds due to malnutrition. There is low egg production in birds (Moreno, 1989).

Injury:

Inflammation, distension, and hemorrhages of the proventriculus (Moreno, 1989). Diagnosis: This is made by observing the parasite in the deep glands of the proventriculus (Moreno, 1989), as well as glandular atrophy and inflammatory changes in the proventriculus. Most authors consider Tetrameres parasites to be not particularly pathogenic to birds.