An Investigation into the Prevalence of Gastrointestinal Helminths in Pigeons from Zabol, Iran

1. Introduction

The Columbidae family, which includes wild and domestic pigeons, exhibits a wide range of colors and breeds. The Rock Pigeons (Columba livia domestica), also referred to as the urban pigeon, is a well-known domestic variety ( 1 ). The practice of breeding pigeons has become increasingly prevalent in recent years, resulting in a concomitant rise in the number of visits made to veterinary clinics. Since pigeons are frequently located in proximity to poultry farms, there is a possibility that they may be a vector for the transmission of poultry pathogens ( 2 ). It is therefore imperative to undertake further research study and to develop suitable treatment options for these birds. It is common for pigeons to be infected with parasites, including helminths and protozoa ( 3 , 4 ). Pigeons are frequently exposed to single-celled protozoan parasites such as Trichomonas gallinarum, helminths, and ectoparasites, as a result of traditional husbandry practices ( 5 ). Ectoparasites can act as carriers for other parasites, and traditional husbandry practices often prove inadequate for their effective control ( 6 , 7 ). Pigeon-borne parasite infections affect pigeons directly and serve as a vector for parasite transmission to other birds, native birds, and even humans ( 8 , 9 ). Pigeons are particularly susceptible to gastrointestinal helminths, which can lead to nutritional deficiencies, severe enteritis, and intestinal expansion ( 10 , 11 ). In order toPredict the risk of parasitic infection, it is necessary to consider a number of factors, including the pigeon’s age, nutrition, immunity, and livig environment. Pigeons are frequently infected with gastrointestinal helminths, including nematodes, cestodes, and trematodes ( 12 ). The occurrence of trematodes is less common because they require snail hosts. The most prevalent cestode families are the Davaineidae, Dilepididae, and Hymenolepididae ( 13 , 14 ). The objective of this study is to determine the prevalence of gastrointestinal helminth infections in pigeons in Zabol County, Iran, and to generate statistical data to improve the development of prevention and treatment strategies for parasitic diseases.

2. Materials and Methods

2.1. Study Area

Zabol County is located in the southeastern region of Iran's Sistan and Baluchestan province at coordinates 31.0294°N latitude and 61.4974°E longitude. The climate is arid,with scorching summers, temperate winters, and overall dry conditions. As a desert region, Zabol experiences scorching temperatures ranging from a low of between -12°C to a high of 53°C. During July, strong winds from the southwest bring about the formation of sandstorms and dunes.

2.2. Sampling

In the present study, the gastrointestinal helminths of 220 pigeons in Zabol County, which died from various causes, were collected and examined from 2021 to 2022 Additionally, theesophageal and tracheal tissues were also inspected for the presence of parasites. The sample population for this study was derived from recent investigations into the prevalence of parasite infections in pigeons ( 15 ). A total of 220 gastrointestinal tracts from deceased pigeons were examined in Zabol County, Iran. Furthermore, an examination of the esophageal and tracheal tissues was conducted. The digestive tract and stomach were then dissected with scissors, and; the contents were transferred to a container for examination. The entire mucosal was then washed and scraped under warm water pressure (60°C) to remove any residual content, after which it was transferred to the container. To prevent the coiling of nematodes, a hot water solution was applied. The container's contents were rinsed multiple times with a stream of hot water until all particles and debris were removed, and clear water emerged from underneath the sieve. The remaining contents were transferred to a glass bottle containing 70% ethanol. The material was placed in a Petri dish with a black background (black tile) for inspection under light microscopy in order to isolate the worms and digestive contents ( 16 , 17 ). A light microscope was used to separate the worms, which appeared white. Following their isolation, the worms were transferred to containers containing 70% ethanol. The structure of nematodes was observed under a microscope using glycerin and lactophenol. In orderto diagnose cestodes, lactophenol was used to make a few segments transparent and the specimen was then examined under a microscope with 40× and 10× magnification. When appropriate, the carmine acid method was employed for the identification of Platyhelminthes.

2.3. Statistical Analysis

The pigeons were classified according to the following variables: gender, breed, age, drug consumption, and feeding type. The significance of the study was assessed through Chi-square tests the Chi-square tests. All analyses were conducted using the SPSS software version 21. The threshold for statistical significance inthis study is p <0.05.

3. Results

A total of 220 pigeon gastrointestinal tract samples from pigeons were analyzed. Of these 96 (43.6%) were positive for helminth infection. Of the infected samples, 52 exhibited only cestode infection (23.6%), while 14 had nematode infection (6.4%). Furthermore, 30 pigeons exhibited co-infection with both cestodes and nematodes co-infected (13.6%). The identified nematode species included A. columbae in 17 infected pigeons (7.27%) (Figure 1.A), H. truncata in 31 pigeons (14.09%) (Figure 1.B), E. clava in 5 pigeons (1.81%), and H. gallinarum in 2 pigeons (0.9%). The cestodes identified in the study included R. tetragona, which was present in 75 infected pigeons (34.09%), R. echinobothrida in 22 pigeons (10%), R. cesticillus in 1 pigeon (0.45%), R. magninumida in 11 pigeons (5%), and C. digonopora in 4 pigeons (18.18%); (Table 1).

Figure 1.A: The presence of a significant number of A. gallinarum nematodes in the small intestine of a pigeon during necropsy.B: Observation of a notable number of H. truncata nematodes in the gizzard of a pigeon during carcass necropsy.

The results of the Chi-square test indicated a significant correlation between pigeon worm infestations and two factors: drug consumption and age. A Chi-square test revealed a significant correlation between the administration of drugs and the incidence of pigeon worm infestation (p=0.001).Moreoverthe older pigeons exhibited significantly higher rates of worm infestation compared to younger pigeons (p=0.00001), However, no significant correlations were observed between worm infestation and gender,breed, or feeding type (P>0.05). When nematode and cestodes infections were considered separately, significant correlations were observed between nematodes and pigeon age (p=0.00008) and between cestodes and both pigeon age and drug consumption (p=0.009). A higher prevalence of nematode and cestode infestations was observed in older pigeons.With a greater incidence of and cestode infestations noted in non-drug-treated birds (Table 2).

4. Discussion

It is a common practice worldwide to keep pigeons for various purposes, including, but not limited to, entertainment and participation in flying competitions. Pigeonsare susceptible to a variety of parasites, including helminths. In addition to causing harm to pigeons, these infections have the potential to spread to native birds and even humans ( 18 ). The gastrointestinal tracts of pigeons can be infested with helminths, including nematodes, cestodes, and trematodes ( 12 ). The results of this study indicate thatcestodes and nematodes are relatively prevalent in Zabol, Iran.

During this study, approximately 43.6% of the sampled pigeons tested positive for parasites, with 23.6% exhibiting exclusive cestode infections, 6.4% nematode infections, and 13.6% co-infections in Zabol County. The prevalence of parasite infections in domestic pigeons was assessed across diverse geographicalregions of Iran.In a study conducted by Ashrafi-Helan et al. (2010) in Tabriz, a variety of parasites were identified. Of these Capillaria obsignata was the most prevalent while A. columbae was the least common ( 19 ). Borji et al. (2012) reported a prevalence of 21.6% for cestodes and 15.3% for nematodes ( 20 ). Islami et al. (2012) identified R. magninumida, R. tetragona, and Cheilospiura hamulosa were discovered in pigeons in Ilam by Islami et al. (2012) ( 21 ). A. columbae, H. truncata, and Raillietina species were identified in domestic pigeons in another study by Radfar et al. (2012) ( 22 ).

In their study of domestic pigeons in Tanzania's Morogoro region, Msoffe et al. (2009) identified three distinct types of intestinal helminths ( 23 ). It is possible that environmental factors may have contributed to the increased prevalence of R. echinobothrida. The prevalence of infestation was found to be influenced by a number of factors, including a lack of of vector control, poor hygiene practices, and the ineffectiveness of treatment. Cestodes were more prevalent in adult birds, whereas nematodes were more common in nestlings. The study by Parsani et al. (2010) concentrated on fecal examination and identified A. columbae and C. obsignata in pigeons in Gujarat, India ( 24 ). A warm and humid climate may facilitate the development of parasite eggs in the region, whereas a dry environment may reduce the probability of parasite egg survival in Zabol. As stated by Al-Bayati (2011), cestodes (Aporina delafondi, Cotugnia intermedia, and Raillientina microcantha) are prevalent in Iraq, with a prevalence rate of 0.73% ( 17 ). Ashraf et al. (2011) reported that 41.3% of male and 39.7% of female pigeons had C. obsignata and A. columbae in their feces. The prevalence of A. columbae and C. obsignata was found to be higher in male subjects. Additionally,Fenbendazole was demonstrated to be a more efficacious treatment for these nematodesthan albendazole ( 25 ). As reported by Diakou et al. (2013), cestodes were identified in wild pigeons in Thessaloniki, Greece, including R. echinobothrida, R. cesticillus, and R. tetragona. The prevalence of R. echinobothrida and R. cesticillus was found to be more prevalent in their study than they were in the present study, whereas the prevalence of R. tetragona was found to be less prevalent ( 26 ). This discrepancy may be attributed to the absence of specific intermediate host species in Greece. In Gujarat, India, Parsani et al. (2014) conducted a study examining the prevalence of helminth parasites in wild and caged pigeons. They identified nematode species, including A. columbae and C. obsignata, as well as several cestode species, including R. echinobothrida, R. tetragona, R. cesticillus, C. digonopora, and Hymenolepis ( 24 ). In comparison to the present study, the aforementioned study identified a higher prevalence of nematodes but a lower prevalence of cestodes, which may be attributed to the India's warmer and more humid climate, which promotes the survival of eggs. It is imperative to exercise caution when interpreting variations in parasite prevalence, taking into account factors such as sample size, study design, methodology (necropsy or fecal examination), and geographic location. It is imperative that further research be conducted on the prevalence of gastrointestinal parasites in pigeons and the effects they have on these birds. The results of the current study indicate that parasites belonging to the cestode group such as R. tetragona and C. digonopora from the cestode group, as well as parasites belonging to the nematode group, including H. truncata and A. columbae, are more prevalent. Notwithstanding the arid conditions, cestodes and nematodes are relatively prevalent in Zabol. As a consequence of their adaptation to the environment, represent a threat to the health of pigeons. It is therefore imperative that a control and prevention program be implemented to protect pigeons and other native birds against these parasites.

Acknowledgment

We would liketo express our gratitude toDr. Soheil Sadr. We would like to express our gratitude to the research deputy of the Ferdowsi University of Mashhad for their invaluable support.

Authors' Contribution

Conceptualization: [EE], Methodology: [EE/HB], Formal analysis and investigation: [JK/EE], Writing-original draft preparation: [NL/MM]; Writing-review and editing: [NL/MM], Funding acquisition: [EE], Supervision: [EE] All authors checked and approved the final version of the manuscript for publication in the present journal.

Ethics

All applicable international, national, and/or institutional guidelines for the care and use of animals were adhered to.

Conflict of Interest

The authors declare they have no conflict of interest.

Funding:

This study was financially supported by Ferdowsi University of Mashhad, Iran (project nos. 55628).

Data Availability

The datasets generated during and/or analyzed during the current study are available from the corresponding author upon reasonable request.

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