The prevalence of coccidial infection in domestic pigeons (Columba livia domestica) from Shanghai was examined in May 2017. A total of 254 fecal samples (210 from meat pigeons and 44 from homing pigeons) were examined; oocysts were identified to the species level based on morphological features. The overall prevalence of coccidian infection was 52.8% (134/254), with prevalence of 55.2% (116/210) for meat pigeons and 40.9% (18/44) for homing pigeons. 5 species of Eimeria were identified, namely, Eimeria labbeana, E .kapotei, E. duculai, E. columbae and E. columbarum. The most common Eimeria species in meat pigeons and homing pigeon pigeons was E. labbeana and E. columbarum, respectively. E. duculai was recorded for the first time in pigeons in China. Concurrent infection with 2-5 species was common. The results of the present investigation have implications for the control of coccidial infections in domestic pigeons in Shanghai.

Dong H, Zhao Q, Zhu S, Han H, Huang B (2018) Prevalence of Eimeria infection in domestic pigeons (Columba livia domestica) in Shanghai, China. J Vet Med Res 5(8): 1155.

Coccidia are protozoan parasites that can affect a wide variety of mammalian and avian species, and they are common pathogenic parasites in pigeons [1]. The subclinical infection is most common, with the pigeons being asymptomatic carrier. Clinical coccidiosis occurs only after massive ingestion of sporulated oocysts, especially in young squabs, or when immunesuppressive condition is present [2]. A greenish diarrhea is the primary clinical sigh, alone with weakness, ruffled appearance, and anorexia [3]. The reported prevalence of Eimeria infection in pigeons was 15.1% in Turkey [4], 36% in Germany [5], 49.2% in Nigeria [6], 50% in Belgium [7], 71.9% in Slovenia [8], 35.8% in USA [9], and 11.5% in Chile [10].

In China, the first report of coccidiosis in pigeons occurred in 1984 [11]. Since then, pigeon coccidiosis has been reported in a limited number of areas. The prevalence ranges from 45.7% to 91.4%, depending on the geographic area [12-15]. However, there have been no studies of prevalence in Shanghai. Therefore, the aim of this study was to determine the prevalence of Eimeria spp. in pigeons in Shanghai, China.

Fecal sampling

In total, 210 and 44 fresh fecal samples were collected from 2 meat pigeon farms and 1 homing pigeon farm from Shanghai in May 2017, respectively. The choice of farms depended on the cooperation of the animal owners. The collected samples were stored at 4°C until being examined.

Oocyst counting

.Each fecal sample was examined for the present or absence of coccidian oocysts by a flotation technique using saturated solution of sodium chloride. Coccidian oocysts per gram (OPG) of feces were determined quantitatively by a modified McMaster technique [16]. Briefly, two grams of fecal material was mixed thoroughly with 30 ml of tap water and filtered through a 150- mm mesh copper sieve. The filtrate was centrifuged at 3,000 g for 5 min. The sediment was suspended with saturated sodium chloride solution, with a final volume of 30 ml, and mixed completely. Two McMaster counting chambers (2×0.15 ml) were filled with the suspension and examined with the use of a light microscope after standing for 10 min. The mean number of oocysts in the 2 chambers was multiplied by the dilution factor (100) to obtain the number of OPG. This method has a sensitivity of 100 oocysts per gram of feces.

Species identification of Eimeria

The remainder of each positive fecal sample was suspended with 2.5% potassium dichromate solution and incubated at room temperature for several days to allow oocysts to sporulate. For identification, a flotation of the sediment in saturated sodium chloride solution was performed. Oocysts identification were made with the use of light microscopy at 400×magnification, according to their sizes and morphological characteristics (shape, colour, form index, presence or absence of micropyle and its cap, presence or absence of residual, polar and Stieda bodies) of the oocysts and sporocysts [17].

Table 1: Prevalence of Eimeria infection in domestic pigeons in Shanghai, China.

Table 2: Species of Eimeria identified and their prevalence in domestic pigeons in Shanghai, China.

Table 3: Number of coccidia species present in individual positive fecal samples of domestic pigeons in Shanghai, China.

Differences in prevalence and average OPG of coccidia between meat pigeons and homing pigeons, as well as between different regions were evaluated using a Chi square test in SPSS for Windows (SPSS 12.0 for Windows, SPSS Inc., Chicago, Illinois), and a value of P < 0.05 was considered significant.

Coccidiosis in pigeons has been reported worldwide. In the present survey, Eimeria oocysts were found in 134 of 254 fecal samples (52.8%) obtained from the three pigeon farms (Table I), showing that infections with coccidia in pigeons are very common in Shanghai. Our results are similar to those reported in Belgium, Guangdong province of China and Nigeria [6,7,11] but lower than the data reported in Slovenia and Henan province of China [8,14]. Many factors may contribute to the different prevalence, including climatic conditions, farm practices, and pigeon breeds.

The prevalence of meat pigeons (55.2%) and the average OPG (52 110) were much higher than that of the Homing pigeons (40.9% and 37 583) (P<0.05), respectively. The prevalence of meat pigeons in Fengxian district (60.9%, 67/110) was much higher than that in Nanhui district (49.0%, 49/100) (P<0.05). However, the average OPG of Nanhui District (88 634) was much higher than that of the Fengxian district (25 400) (P<0.05) (Table I). These results indicate that the prevalence of Eimeria spp. infection varies dramatically between regions and breed groups.

To date, 9 species of Eimeria have been documented from pigeon worldwide [1]. In China, 5 Eimeria species have been found in pigeons, namely E. labbeana, E. tropicalis, E. kapotei, E. columbarum and E. columbae [12-15]. But in the present study, we found five species in meat pigeons and four in homing pigeons (Table II). One species, E. duculai, was recorded for the first time in pigeons in China. The most commonly found species in meat pigeons was E. labbeana. In homing pigeons, E. columbarum was the more frequently found. Mixed infection with two or three Eimeria species was more commonly seen than infection with a single Eimeria species (Table III), consistent with the findings of other researchers [14,15,18].

In Europe, coccidiosis in racing pigeons is caused primarily by E. labbeana and E. columbarum [2]. Though these two species were found to be the most prevalence species in meat pigeons and homing pigeons in the present study, but no cases of clinical coccidiosis were found and all the pigeons appeared healthy. As the intensity of Eimeria infection (estimated as average OPG) in meat pigeons and homing pigeons was 52110 and 37583, respectively, subclinical infections are likely to be frequent in the three pigeon farms in Shanghai. The disease may occur under stress factors such as weaning, dietary changes, inclement weather or travel and regrouping. Therefore, it is necessary to carry out integrated strategies to control coccidial infection in this area.

Infections with coccidia in pigeons are very common in Shanghai. The results of the present investigation have implications for the control of coccidial infections in domestic pigeons in Shanghai.

The authors thank all the veterinary surgeons who cooperated in sample collection

HD and BH conceived and designed the experiments. QZ, HH and SZ helped to carry out various aspects of the experiments. HD and HB drafted and revised the manuscript. All authors read and approved the final version of the manuscript.

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