Parasites in Chicken Meat: Common Pathogens and Food Safety Implications

Introduction

The global poultry industry provides a major source of high-quality animal protein through meat and eggs [1, 2]. However, parasitic infections in chickens remain a significant constraint on productivity and food safety [3]. Contamination of chicken meat with parasitic pathogens can occur at multiple points from farm to fork, influenced by management systems, hygiene practices, and geographic region [4, 5]. This article reviews the common parasites found in chicken meat, their biological characteristics, epidemiological patterns, clinical consequences in poultry, diagnostic approaches, control strategies, and food safety risks. For a complementary discussion of zoonotic aspects, readers are referred to the existing article Are There Parasites in Chicken Meat and Eggs? Assessing Food Safety Risks.

Etiology of Parasites in Chicken Meat

Parasites identified in chicken meat encompass protozoa, nematodes, cestodes, trematodes, and ectoparasites. The most economically significant protozoan pathogens are coccidian species of the genus Eimeria, which cause coccidiosis [1, 6]. Seven pathogenic species infect chickens, including Eimeria tenella, Eimeria acervulina, Eimeria maxima, Eimeria necatrix, Eimeria brunetti, Eimeria mitis, and Eimeria praecox [1, 7]. These obligate intracellular parasites invade intestinal epithelial cells, leading to hemorrhagic enteritis, malabsorption, and reduced growth performance [1, 8].

Helminth parasites are also prevalent in chicken meat and offal. Nematodes such as Ascaridia galli, Heterakis gallinarum, Capillaria spp., Syngamus trachea, and Tetrameres americana have been recovered from gastrointestinal tracts and occasionally from liver tissues [2, 9, 10, 32]. Cestodes, including Raillietina tetragona, Raillietina echinobothrida, Davainea proglottina, and Choanotaenia infundibulum, are commonly reported in free-range and backyard flocks [11, 2, 32]. Trematodes such as Prosthogonimus spp. infect the oviduct and can be found in meat if visceral contamination occurs [2].

Protozoan parasites with zoonotic potential include Toxoplasma gondii and Neospora caninum [28, 30, 31]. Toxoplasma gondii tissue cysts may localize in muscle and brain, persisting for the life of the host [31, 33]. Neospora caninum DNA has been detected in chicken leg meat, raising concerns about foodborne transmission to canids and potentially humans [28]. Sarcocystis spp., another cyst-forming coccidian, has been molecularly identified in ready-to-eat meat products containing poultry [33].

Ectoparasites such as feather lice (Menopon gallinae, Menacanthus stramineus), fleas (Echidnophaga gallinacea), and mites (Ornithonyssus sylviarum, Laminosioptes cysticola) are not typically found in muscle meat but may contaminate carcasses during processing [12, 13, 14]. Their presence in meat products is considered a hygiene indicator [4].

Epidemiology and Prevalence

The prevalence of parasites in chicken meat varies widely based on production system, geographic location, and diagnostic method. Coccidiosis caused by Eimeria spp. is endemic in most poultry operations, with prevalence rates reported as high as 68.6% in broiler farms and 34.5% in grandparent and parent stocks [15]. In southern Punjab, Pakistan, a survey of 500 samples found 58% positive for Eimeria species, with E. maxima and E. acervulina being most common [7]. In Gharb, Morocco, coccidiosis was documented as a major concern in chicken meat [3].

Helminth infections are particularly common in indigenous and free-range chickens. In Ghana, an overall prevalence of 65.5% was recorded among 200 cloacal samples, with Ascaridia galli (32.5%) and Heterakis gallinarum (19.0%) dominating [2]. In Penang, Malaysia, 14 helminth species were identified from 240 indigenous chickens, including Acuaria hamulosa, Gongylonema ingluvicola, and Oxyspirura mansoni [9]. Studies in Nigeria reported prevalence rates of 51.53% (163 chickens) and 26% (150 chickens) for gastrointestinal helminths [10, 32]. In Abakaliki, Nigeria, local chickens showed high parasite loads impacting meat quality [11].

For protozoan parasites, Toxoplasma gondii DNA was detected in 23% of chicken leg samples and 36% of free-range eggs in Semnan, Iran [31]. Conversely, a study in Kayseri, Türkiye, found no T. gondii DNA in 25 chicken meat and 25 chicken liver samples, though the authors noted that low parasitic load and sample size may influence results [30]. Neospora caninum DNA was detected in 8% of chicken legs in Iran [28]. In Switzerland, 14.9% of ready-to-eat meat products (including poultry) were positive for T. gondii DNA, and 58.2% for Sarcocystis spp. DNA, with 29.6% of beef-containing samples positive for zoonotic S. hominis [33].

Table 1 summarizes prevalence data from selected studies.

Clinical Signs and Pathology in Chickens

Parasitic infections in chickens often result in subclinical or clinical disease that affects meat quality. Coccidiosis caused by Eimeria species leads to diarrhea, decreased feed efficiency, reduced weight gain, and mortality in severe cases [1, 8]. Eimeria tenella causes cecal hemorrhage and is particularly pathogenic [7]. Infection disrupts the intestinal epithelium, leading to malabsorption and oxidative stress in breast meat, as evidenced by reduced carotenoid and vitamin E levels [8].

Helminth infections, especially with Ascaridia galli, cause intestinal blockage, stunted growth, and predispose birds to secondary bacterial infections [2, 9]. Heterakis gallinarum is important as a vector for Histomonas meleagridis, which causes blackhead disease in turkeys, though this is less relevant in chickens [2]. Cestodes such as Raillietina spp. attach to the intestinal wall and can cause enteritis and reduced nutrient uptake [32].

Toxoplasmosis in chickens is typically subclinical, but tissue cysts persist in muscle and brain, making them a source of infection for carnivores and humans [31]. Neospora caninum infection in chickens has not been associated with overt clinical signs, but the detection of DNA in meat suggests tissue parasitism [28].

Meat quality parameters affected by coccidiosis include increased lipid oxidation (measured as malondialdehyde) and reduced antioxidant capacity [8, 29]. Dietary supplementation with nanocurcumin has been shown to restore carotenoid and vitamin E levels in breast meat of infected birds, indicating that nutritional management can mitigate quality deterioration [8]. Herbal mixtures containing ginseng and artichoke also improved meat color and water-holding capacity in slow-growing chicken breeds [29].

Diagnostics

Detection of parasites in chicken meat relies on macroscopic examination, microscopy, molecular assays, and serological methods. For Eimeria species, oocyst identification using flotation techniques and McMaster counting is standard [1, 7]. Species differentiation requires morphometric analysis of sporulated oocysts or molecular methods such as species-specific polymerase chain reaction (PCR) [7].

Helminth eggs and larvae can be detected by sedimentation and flotation techniques from intestinal contents or fecal samples [2, 10, 32]. For meat inspection, direct tissue compression or artificial digestion may be used to recover encysted protozoans, though these methods have low sensitivity.

Molecular diagnostics offer high sensitivity and specificity. A nested multiplex PCR assay has been developed to detect Toxocara canis, Toxocara cati, and Ascaris suum contamination in meat, with detection limits of 10 fg for T. canis and 1 fg for T. cati [16]. Although this assay targets ascarids in general, it demonstrates the utility of nested PCR for detecting low-level parasitic DNA in meat matrices [16]. For Toxoplasma gondii, real-time PCR targeting the B1 gene is widely used [30, 31]. Neospora caninum detection employs nested PCR of the ITS-1 region [28]. Sarcocystis species can be identified by PCR followed by Sanger sequencing of the 18S rRNA gene [33].

Figure 1 illustrates a general diagnostic workflow for detecting parasites in chicken meat.

flowchart TD
    A[Chicken meat / organ sample], > B{Macroscopic inspection}
    B, >|Visible cysts or lesions| C[Direct microscopy / tissue squash]
    B, >|No visible lesions| D[DNA extraction from homogenate]
    D, > E{Molecular detection}
    E, > F[PCR / real-time PCR for target parasites]
    F, > G[Electrophoresis and sequencing]
    C, > H[Flotation / sedimentation for eggs and oocysts]
    H, > I[Light microscopy identification]
    G, > J[Species confirmation]
    I, > J
    J, > K[Report result and risk assessment]

Treatment and Control

Control of parasites in chicken meat involves integrated management of biosecurity, chemotherapy, vaccination, and alternative feed additives. For coccidiosis, anticoccidial drugs such as ionophores and chemical compounds are widely used, but resistance has emerged, prompting a need for novel strategies [1, 6]. Vaccination with live attenuated Eimeria oocysts is employed in some breeding flocks [1].

Helminth control relies on anthelmintics such as benzimidazoles and macrocyclic lactones, though resistance is also a concern [9, 17]. In free-range systems, rotational grazing and removal of litter reduce environmental contamination [9]. Plant extracts have been investigated as alternatives. Belimbing wuluh (Averrhoa bilimbi) leaf extract was tested in vivo against Ascaridia galli and Raillietina sp., but concentrations up to 35% did not significantly reduce worm burdens [17].

For protozoan parasites, no licensed treatments for Toxoplasma or Neospora in chickens exist. Prevention focuses on biosecurity to break the life cycle, including preventing access of cats (definitive hosts for T. gondii) and canids (definitive hosts for N. caninum) to poultry premises [28, 31]. Irradiation of animal-origin foods, including chicken meat, is an effective nonthermal method to inactivate parasites and microorganisms; however, consumer acceptance remains a challenge [18].

Natural feed additives have shown promise. Nanocurcumin supplementation at 400 mg/kg feed improved antioxidant stability and meat quality in Eimeria-infected broilers [8]. A herbal mixture of ginseng and artichoke improved growth performance and meat quality in slow-growing Hanhyup-3-ho chickens, while also reducing excretal ammonia and hydrogen sulfide emissions [29]. These approaches align with the push to reduce antibiotic and anticoccidial residues in meat [1, 27].

Table 2 summarizes common control measures and their targets.

Food Safety Implications

The presence of parasites in chicken meat poses food safety risks primarily through zoonotic transmission. Toxoplasma gondii is a major concern because undercooked meat containing tissue cysts can cause toxoplasmosis in humans, leading to severe disease in immunocompromised individuals and congenital infections [30, 31, 33]. Detection of T. gondii DNA in 23% of chicken legs and 36% of free-range eggs underscores the potential for foodborne transmission [31]. Similarly, Neospora caninum DNA in 8% of chicken meat raises questions about its zoonotic potential, though definitive evidence of human infection is lacking [28].

Sarcocystis hominis and S. suihominis are zoonotic, causing intestinal sarcocystosis. The detection of S. hominis in 29.6% of beef-containing products and S. suihominis in 3.2% of pork-containing products, but not in poultry-only samples, suggests that chicken meat may pose lower risk for this parasite [33]. However, Sarcocystis spp. DNA was detected in 58.2% of mixed meat products, highlighting the need for species-level identification [33].

Bacterial contamination often co-occurs with parasitic infections. A study in Iraq found that chicken products (burger, shawarma, liver) harbored bacterial species such as Aeromonas veronii, Pseudomonas spp., and Klebsiella pneumoniae [19]. While primarily bacterial, these findings indicate general hygienic failures that may also permit parasitic contamination [19, 4, 20]. Parasitic eggs of hookworm and Ascaris lumbricoides have been found in bulk chicken meat sold in supermarkets, along with insect parts, indicating cross-contamination during handling [4].

Residues of anticoccidial drugs in chicken meat are another food safety concern. Coccidiostats such as monensin and salinomycin are regulated with maximum residue limits, and analytical methods like LC-MS/MS are used for quantification [27]. The emergence of drug-resistant Eimeria strains may lead to increased use of alternative therapies, potentially introducing new residues [1, 35].

Parallels with other livestock exist; for example, Trichinella spiralis in Wild Boar: Food Safety Surveillance and Public Health Risks illustrates similar concerns for pork. The principles of effective cooking temperature and handling apply broadly, as discussed in Food Safety and Chicken: Killing Bacteria Through Proper Cooking and Handling. For comprehensive food safety guidance, readers may consult Parasites in Chicken Meat: Food Safety and Public Health Concerns.

Conclusion

Parasites in chicken meat represent a multifaceted challenge for veterinary medicine and food safety. Major pathogens include coccidia (Eimeria spp.), helminths (nematodes and cestodes), and zoonotic protozoa (Toxoplasma gondii, Neospora caninum). Prevalence varies with management systems and geography, with high infection rates in free-range and backyard flocks. Diagnostic methods ranging from microscopy to advanced PCR enable detection, but surveillance gaps remain in many regions. Control requires integrated strategies combining biosecurity, chemotherapy, vaccination, and natural feed additives to reduce parasite burden and drug residues. Food safety risks can be mitigated through proper cooking, irradiation, and adherence to hygiene standards. Continued research into parasite biology, transmission, and novel control tools is essential to safeguard poultry production and public health.

References

[1] Nguyen BT, Flores RA, Kim T, et al. Understanding Eimeria infection for the treatment and prevention of chicken coccidian parasites. Frontiers in Cellular and Infection Microbiology. 2026. URL: https://www.semanticscholar.org/paper/ed176b6c07cbbc02de6e3c7584875196c70e2aaa

[2] Asumang P, Delali JA, Wiafe F, et al. Prevalence of Gastrointestinal Parasites in Local and Exotic Breeds of Chickens in Pankrono–Kumasi, Ghana. Journal of Parasitology Research. 2019. URL: https://www.semanticscholar.org/paper/c8e2a55d1bbee4ea1cf2c153dacda4d1773ecff0

[3] Hachimi M. Coccidiosis in chicken meat in Gharb region of Morocco. 2017. URL: https://www.semanticscholar.org/paper/0a90b9fcfa474e816d2f1739c5466228ce0d8d5f

[4] Dias O, Cardoso AAS, Santos L, et al. HYGIENIC-SANITARY PROFILE OF HANDLED MEAT SOLD IN BULK IN SUPERMARKET CHAINS IN TERESINA-PI. 2020. URL: https://www.semanticscholar.org/paper/1ffc44a66a0e4d2aab6787c060b0fed90999cba7

[5] Afolabi KD. Local or Indigenous Chicken Production: A Key to Food Security, Poverty Alleviation, Disease Mitigation and Socio-Cultural Fulfilment in Africa. 2013. URL: https://www.semanticscholar.org/paper/70ae30ebe3fff79db1521bd43942891494e4cc4e

[6] Madlala T, Okpeku M, Adeleke M. Understanding the interactions between Eimeria infection and gut microbiota, towards the control of chicken coccidiosis: a review. Parasite. 2021. URL: https://www.semanticscholar.org/paper/825a7c61ae9c2998f6de55258591153f0349800b

[7] Khan MJ. Epidimiological studies of different eimerian species and their identification in commercial poultry of southern Punjab, Pakistan. Frontiers in Nanoscience and Nanotechnology. 2019.

[8] Partovi R, Seifi S, Pabast M, et al. Effect of dietary supplementation of nanocurcumin on oxidant stability of broiler chicken breast meat infected with Eimeria species. Veterinary Research Forum. 2020. URL: https://www.semanticscholar.org/paper/1118d92077c35f65a1b32fac9c868d38479cf9a4

[9] Farah Haziqah MT, Khadijah S. Helminthic parasites in indigenous chickens in Penang Island, Malaysia. Tropical Biomedicine. 2020. URL: https://www.semanticscholar.org/paper/4e9b5e8f35c57b7e89345ba8c02dae0f1a76ae47

[10] Abdullahi M, Jacob SA, Hassan H. STUDY OF THE INTESTINAL PARASITES OF CHICKENS SLAUGHTERED AT KEFFI MAIN MARKET, NASARAWA STATE, NIGERIA. FUDMA Journal of Sciences. 2023. URL: https://www.semanticscholar.org/paper/93744217aff2d83ecfc807f91f48a09c8746ee4a

[11] Uhuo AC, Okafor F, Odikamnoro O, et al. Common gastrointestinal parasites of local chicken (Gallus domesticus) slaughtered in some selected eatery centres in Abakaliki, Ebonyi State: Implication for meat quality. 2013. URL: https://www.semanticscholar.org/paper/3fcf77b0b8eb4d0599849db89322dd8aba1e36dd

[12] Kebede W. Investigation of Major Ecto-Parasite Affecting Backyard Chicken in Bishoftu Town, Ethiopia. Journal of Medicine and HealthCare. 2019. URL: https://www.semanticscholar.org/paper/e6cb22c52c14deb2d4164590430e919c0d31351d

[13] Serda B, Abdi M. Prevalence of Ectoparasites Infestation in Poultry in Haramaya District, Eastern Hararghe Zone; Oromia Region, Ethiopia. 2018. URL: https://www.semanticscholar.org/paper/b3f1c9c6cd6e22cc53e60530be26d3316fdbe4bf

[14] Tavakkoli H, Moeini E, Khedri J, et al. Occurrence of Laminosioptes cysticola mite in broiler poultry and proposed solutions to prevent infestation. Journal of Parasitic Diseases. 2018. URL: https://www.semanticscholar.org/paper/bf87f08c55a1c8683646151f1509d1b0e3d8c605

[15] Alamin FM, Masli EA, Adem SS, et al. A study of the prevalence of coccidiosis (Eimeria spp.) in broiler and grand–parent and parent chicken farms in Ghot sultan poultry and dairy project. المجلة الليبية العالمية. 2023. URL: https://www.semanticscholar.org/paper/f679d0dc5833fe15ba6db0ebf1a9af31b2a18c84

[16] Wang Z, Shibata M, Nguyen YTH, et al. Development of nested multiplex polymerase chain reaction (PCR) assay for the detection of Toxocara canis, Toxocara cati and Ascaris suum contamination in meat and organ meats. Parasitology International. 2018. URL: https://www.semanticscholar.org/paper/a43c1124d17f18d8ac00d6c34b8fbe35de126932

[17] Moenek DYJA, Toelle NN, Oematan AB. Potensi Antilmintik Ekstrak Daun Belimbing Wuluh (Averrhoa bilimbi) Secara In Vivo Terhadap Cacing Intestinum Ayam Kampung (Gallus domesticus). Jurnal Kajian Veteriner. 2023. URL: https://www.semanticscholar.org/paper/c1dd7ff6b4be7f4cb11a5a7c0102bcbb06cdfc33

[18] Xavier MMBBS, Franco R, Souza MCL, et al. Implications of the use of irradiation in the processing of animal origin foods: Review. 2018. URL: https://www.semanticscholar.org/paper/ed6dd4ed05e32c992f3ee092ee6d3dc2e5eba60dc

[19] Husain DA, Aziz ZS. Short Communication: Molecular study of bacteria isolated from meat and chicken frozen from Misan Governorate market in Iraq. Biodiversitas Journal of Biological Diversity. 2021;23:81-86. URL: https://www.semanticscholar.org/paper/6d98992f4e7d83a45b10e8e44c1738b76a18f1c5

[20] Mgbemena I, Ebe T, Nnadozie A, et al. Bacterialogical And Parasitological Assessment Of Fresh Meat Marketed In Owerri, Imo State, Nigeria. 2015. URL: https://www.semanticscholar.org/paper/134db71c0c276f30bdcc12822ffa78dbbecec0f7

[21] Gicheha MG, Gikunju MM, Ouko O, et al. Genetic and morphological diversity of indigenous chicken of Kenya: A Review. Journal of Agricultural Science and Technology. 2026. URL: https://www.semanticscholar.org/paper/73dbd105d08cbaf8f5f77562f541d10dae04ea18

[22] Hilemàn B. ARSENIC IN CHICKEN PRODUCTION. 2007. URL: https://www.semanticscholar.org/paper/d5e7052fec017e29e4b44e6159d28f6feb59c434

[23] Hernandez-Divers S, Villegas P, Prieto F, et al. A Survey of Selected Avian Pathogens of Backyard Poultry in Northwestern Ecuador. 2006. URL: https://www.semanticscholar.org/paper/a4f9ba86e7b3822ff5cb87d3b8cebb87ba9e63c0

[24] Farah Haziqah MT. 896-902-Farah Haziqah-MT.pmd. 2020. URL: https://www.semanticscholar.org/paper/9c44aefd95bc5de79af0ac48cc586e7f249795ac