Eimeria phasiani Tyzzer, 1929

Malikova, Zamina K. & Ahmadov, Elshad I., 2023, Coccidial fauna of pheasants (Phasianus colchicus colchicus), Amurian Zoological Journal XV (1), pp. 155-161 : 158-160

Eimeria phasiani Tyzzer, 1929 (Syn. Eimeria phasiana , lapsus in Tyzzer, 1929)

Oocysts have elliptical or stretched elliptical shape. The dimensions are 23.5– 32.40 × 16.19–18.99 μm, on average — 28.41 ± 2.60 × 17.80 ± 1.60 μm. The oocyst wall is smooth, double-contoured, yellowgreen. The form index varies between 1.45– 1.71, on average — 1.60 ± 0.07. No micropile and no residual body.

In recently excreted oocysts, the granular protoplasmic mass extends to both poles and takes a broad oval shape. Sporulated oocysts contain one to two polar granules. Micropile abscent. In sporulated oocysts, four stretched sporocysts with elliptical shape are formed. The maximum size of spores is 16.2 × 8.1 μm, the minimum size is 11.1 × 5.7 μm, and the average size is 13.1 x 5.9 μm. There is the Stieda body at the tip of the sharp point. Two comma-shaped sporozoites are observed in each spore. The dimensions are 3.5–7.9 × 2.7– 5.4, on average —5.9 × 4.0 μm. A small grainshaped residue is noted only in spores.

Isospora sp. oocysts found in the faecal samples are ellipse- or ovoid-shaped. The wall is two-layered. Micropile abscent. The dimensions of oocysts are 29.0– 32.89 × 20.85–27.11 μm, on average — 31.03 ± 1.90 × 23.99 ± 3.19 μm, and form index is 1.29 (Table 2).

Residual bodies are found in oocysts and sporocysts. The results of the measurements show that the shape of oocysts found in the isolates is stable while their dimensions (length and width) differ slightly.

Discussion

Coccidiosis caused by Eimeria can result in a large number of deaths and significantly reduce productivity of pheasants raised in artificial conditions. Coccidiosis still remains one of the dangerous diseases of animals. In natural conditions pheasants are rarely infected with only one of the Eimeria species. Infection usually occurs as a mixed infestation. Clinical signs of the disease depend on the number of oocysts. Regular contamination of the environment by sick birds with oocysts leads to infection of healthy birds.

Currently 10 species of genus Eimeria are known to parazitize pheasants ( Peilerdy 1974). Pheasants are reported to be infect- ed with Eimeria colchici , Eimeria dispersa , Eimeria duodenalis , Eimeria gennaeuscus , Eimeria langeroni , Eimeria megalostomata , Eimeria pacifica , Eimeria picta , Eimeria phasiani and Eimeria tetartooimia of genus Eimeria ( Norton 1976; 1986; McQuistion 1987; Vanparijs et al. 1990; Lilić et al. 2013). Among these species, Eimeria colchici is a pathogenic and common species in pheasant farms and distinguished by high reproduction rates ( Norton 1976). Norton reports the discovery of E. duodenalis and E. colchici species in England ( Norton 1967).

Golemansky reports five species — E.duodenalis Norton, 1967 , E.megalostomata Ormsbee, 1939 , E. pacifica Ormsbee, 1939 , Eimeria colchici Norton, 1967 — of genus Eimeria parasitizing pheasants in Bulgaria ( Golemansky 2017). Although Musaev and Aliyeva ( Musaev, Alieva 1983) reported on the discovery of E. phasiani , E. pacifica , E. duodenalis and Isospora sp. in pheasants in Azerbaijan, they provided no information about their size. Musaev, Gaibova and others state that one species of Eimeria , E. phasiani , was found in pheasants in Azerbaijan ( Musaev et al. 1998). It was reported that in the United States, E. colchici and E. phasiani species of Coccidia cause eimeriosis among pheasants ( Gerhold et al. 2010).

Comparison of the conclusions of their research with the conclusions of similar studies conducted around the world shows that coccidia are widespread among pheasants. We found Eimeria colchici , Eimeria phasiani and Eimeria duodenalis of genus Eimeria in the pheasants studied in Absheron. The most frequently occurring species was Eimeria colchici (86.67%).

E.phasiani and E. duodenalis species are found in Germany. Both species were found in 41% of the pheasants studied. Reports reveal that E.phasiani , E. duodenalis , and E. colchici species were found in England ( Williams 1978) and USA ( Fuller et al. 2008). Fisher notes that the infection extensiveness of pheasants in Iowa farms with E.phasiani species is 75–94% ( Fisher 1973). In Illinois, the infection extensiveness with E.duodenalis species is 57.5%, and the infection extensive-

Table 2

Dimensions of oocysts recorded in spontaneously infected pheasants

ТабAица 2

СвеAения о размерах ооцист у спонтанно зараженных фазанов ness with E.phasiani species is 8.8% ( McQuistion 1987).

A comparative study of the infection of pheasants with different species of Eimeria and Isospora depending on their age shows that E.colchici and E.duodenalis infection prevailed in 1–30-day-old chickens and amounted to 54.55% in both cases. The intensity of E. duodenalis infection in birds was two times higher than that of E. colchici . Out of 18 pheasants aged 31–120 days, oocysts of E. colchci and E. duodenialis were detected in 12 individuals (66.67% in both cases), E. phasiani — in five (27.78%), and Isospora spp . — in one (5.56%). Isospora oocysts were not found in any of the samples taken from 41 pheasants older than 120 days, E. colchci were found in 34 (82.93%), E. duodenialis — in 23 (56.10%) and E. phasiani — in 15 (36.59%).

Thus, the comparison of the conclusions of our research with the results of the similar studies shows that the infection extensiveness of pheasants with E. colchici and E. duodenalis species is very high in Azerbaijan. It is 86.67% and 77.33%, respectively, while the infection extensiveness with İsospora species is very low — 1.67%.

In order to prevent and treat coccidiosis, protection measures should be based on regular parasitological control of pheasants in accordance with modern zoohygiene requirements.

Conclusion

As a result of the coprological examination of pheasants ( Phasianus colchicus colchicus ) kept in cages in Absheron, three species ( Eimeria colchici , Eimeria phasiani , Eimeria duodenalis ) of genus Eimeria and one species ( Isospora sp. ) of genus Isospora were found to be parasitic.

Among infected birds, Eimeria colchici occured most frequently (86.67%), followed by Eimeria duodenalis (77.33%) and Eimeria phasiani (33.33%). The overall infection extensiveness of pheasants with eimeria was very high and amounted to 86.67%. Isospora sp. oocysts were found in 1.67% of the pheasants examined.

The results of the measurements show that the shape of oocysts found in the isolates is stable and their dimensions (length and width) differ slightly.