Abstract
Rabbits (Oryctolagus cuniculus) are frequently reared for meat production in China. The aim of this study was to assess the seroprevalence of Toxoplasma gondii and Encephalitozoon cuniculi, and risk factors of infection in domestic rabbits raised in Henan province, central China. 1,213 serum samples of domestic rabbits were collected and tested for anti-T. gondii and anti-E. cuniculi antibodies using a modified agglutination test (MAT) and an enzyme-linked immunosorbent assay (ELISA), respectively. The serum positive rates of T. gondii and E. cuniculi were 128/1,213 (10.55%) and 235/1,213 (19.37%), respectively. Co-infection of T. gondii and E. cuniculi was demonstrated in 84 specimens; 44 rabbits were seropositive for T. gondii alone, while 151 rabbits were seropositive for E. cuniculi alone. The main risk factors simultaneously associated with T. gondii and E. cuniculi infection were the age of the rabbit, the type of food, and the rabbit rearing system. Serum positive rates of T. gondii and E. cuniculi among domestic rabbits were high, indicating the possibility of public health issues.
Keywords: Toxoplasma gondii, Encephalitozoon cuniculi, domestic rabbit, seroprevalence, central China
Abstract
Les lapins (Oryctolagus cuniculus) sont fréquemment élevés pour la production de viande en Chine. Le but de l’étude était de déterminer la séroprévalence de Toxoplasma gondii et d’Encephalitozoon cuniculi ainsi que les facteurs de risque d’infection chez les lapins domestiques élevés dans la province du Henan, en Chine centrale. 1 213 échantillons de sérum de lapins domestiques ont été collectés et testés pour les anticorps anti-T. gondii et anti-E. cuniculi en utilisant un test d’agglutination modifié (MAT) et un dosage immuno-enzymatique (ELISA), respectivement. Les taux sériques positifs de T. gondii et E. cuniculi étaient de 128/1 213 (10,55%) et de 235/1 213 (19,37%), respectivement. La co-infection par T. gondii et E. cuniculi a été démontrée chez 84 spécimens ; 44 lapins étaient séropositifs pour T. gondii seul, alors que 151 lapins étaient séropositifs pour E. cuniculi seul. Les principaux facteurs de risque associés simultanément à l’infection par T. gondii et E. cuniculi étaient l’âge du lapin, le type d’aliment et le système d’élevage du lapin. Les taux sériques positifs de T. gondii et d’E. cuniculi chez les lapins domestiques étaient élevés, ce qui indique la possibilité de problèmes de santé publique.
Introduction
Toxoplasma gondii (T. gondii) is one of the most common universal zoonotic protozoan parasites, ubiquitous throughout the world, and widely prevalent in humans and animals [8]. It is estimated that up to one-third of the world’s human population has been infected with T. gondii [10]. Almost all warm blooded animals are infected by T. gondii, including rabbits [7]. The main route for humans to acquire T. gondii infection is the consumption of raw or undercooked meat containing tissue cysts from intermediate hosts [8].
The transmission mode of T. gondii to rabbits is through water or food containing oocysts from feline excrement, or through placenta from pregnant females to offspring [8]. Humans may become infected not only by eating undercooked rabbit meat but also from contaminated hand–to-mouth processes after slaughtering, skinning rabbits or dealing with undercooked or raw rabbit meat [4,9].
Encephalitozoon cuniculi (E. cuniculi) is a common pathogen of rabbits causing chronic renal and central nervous system disease characterized by granuloma formation and fibrosis [16]. However, it also affects other mammals, including rodents, herbivores, carnivores, nonhuman primates, and humans [1,6]. Infected rabbits eliminate the spores in urine and feces. Humans become infected principally by intake of water or food contaminated with infective spores. Human encephalitozoonosis is mostly found in immunocompromised patients, including organ transplant recipients, HIV patients, and cancer patients who are being treated with chemotherapy [2]. In many rabbits, the infection can persist subclinically for a long period of time [16].
In China, rabbits are frequently reared for meat production and are consequently considered a possible source of infection by T. gondii and E. cuniculi in humans. However, little is known about natural infection of T. gondii and E. cuniculi in domestic rabbits in China. Therefore, this study was conducted to investigate the seroprevalence and the risk factors related to seropositivity of T. gondii and E. cuniculi among domestic rabbits in Henan province, central China. The results will lay the groundwork for controlling both T. gondii and E. cuniculi infections among domestic rabbits in central China.
Material and methods
Ethical statements
All protocols in this study were reviewed and approved by the Ethics Committee of the Xinxiang Medical University (reference no. 2015018).
The study site
The study was conducted in Henan province, which is situated in the middle section of China with an approximate population of 106.01 million and total surface area of 167,000 km2. The Yellow River flows through the middle section of Henan, which is seated within north latitude of 31°23′−36°22′ and east longitude of 110°21′−116°39′. Due to the mainland monsoon type climate, four seasons are distinct with the year-round average temperature of 12.1-15.7 °C and year-round average precipitation of 532.5-1380.6 mm. Henan province contains seventeen cities and Zhengzhou is the capital city. Seven cities which include Anyang (35°13′−36°22′N, 113°37′−114°58′E), Sanmenxia (33°31′−35°05′N, 110°21′−112°01′E), Luoyang (33°35′−35°05′N, 111°08′−112°59′E), Xuchang (33°16′−34°24′N, 113°03′−114°19′E), Zhumadian (32°18′−33°35′N, 113°10′−115°12′E), Xinyang (31°46′−31°52′N, 114°01′−114°06′E) and Zhoukou (33°03′−34°20′N, 114°05′−115°39′E), located in the northern, western, central, southern and eastern parts of Henan province (Fig. 1), were selected for sample collections. All of the above places account for most rabbit meat supplies to districts in and around Henan.
Figure 1.
Geographic distribution of the sampling sites in Henan province, central China used in this study. A: Henan province (HN, shadowed areas) is located in the central part of mainland China. B: Shadowed areas are the sampling locations for the present survey. AY: Anyang; SMX: Sanmenxia; LY: Luoyang; XC: Xuchang; ZK: Zhoukou; ZMD: Zhumadian; XY: Xinyang.
Collecting samples
A total of 1213 blood specimens of domestic rabbits were collected from the seven above-mentioned cities within Henan province during the period from June 2015 to December 2016. Information on location, species, gender, ages of rabbits as well as the feeding conditions of respective rabbits was recorded. Serum specimens prepared by centrifuging whole blood were subsequently transferred into 1.5 ml Eppendorf tubes and preserved under the temperature of −80 °C before being tested against anti-E. cuniculi and T. gondii antibodies.
Determining anti-T. gondii antibody
Based on previous studies, the anti-T. gondii antibodies in serum specimens were determined using the modified agglutination test (MAT) [8,13,21]. T. gondii whole cell antigen (formalin-fixed whole tachyzoites) prepared using the RH strain of T. gondii cultivated via human foreskin fibroblast cells was purchased from KeraFAST, Inc. (Boston, MA, USA). Briefly, serum samples were diluted by serum dilution buffer using 2-fold serial dilutions from 1:25 to 1:3,200. Fifty microlitres of diluted serum samples were used for agglutinating with 50 µl of antigen mixture (mixture of antigen dilution buffer, 2-mercaptoethanol, Evans blue dye solution, and T. gondii whole cell antigen) in a U-bottom 96-well microtiter plate under the temperature of 37 °C for a whole night. The formation of parasite agglutinating layers in wells which contained diluted serum specimens with a ratio of 1:25 or higher indicated positive results. Each assay contained negative and positive control groups.
Determination of antibodies against E. cuniculi
The anti-E. cuniculi antibody levels of serum samples from domestic rabbits were verified and detected using a commercial Encephalitozoon cuniculi (EC) ELISA kit (Medicago, Uppsala, Sweden), following the manufacturer’s instructions.
Statistical analysis
Chi square tests were used to analyse the variation of serum positive rates for T. gondii and E. cuniculi resulting from variates including species, gender, ages, the type of food, and the rearing system. Windows version SPSS 20 (SPSS Inc, Chicago, IL, USA) was used to perform all statistical analyses. A p-value lower than 0.05 was regarded as the threshold for statistically significant differences.
Results
Seroprevalence of T. gondii
As shown in Table 1, the overall recorded serum positive rate for T. gondii among rabbits from Henan province, central China was 10.55% (128/1213), with titers of 1:25 in 69, 1:50 in 36, 1:100 in 14, 1:200 in 5, 1:400 in 3, and 1:800 in 1. The serum positive rates of 7 sampling sites were within the range of 7.64% in Sanmenxia city to 14.06% in Luoyang city (Table 1). New Zealand rabbits exhibited the maximum value of 12.34%, followed by Chinese rabbits (10.73%) and then Japanese White rabbits (10.58%), while the prevalence found in Rex rabbits was 9.17%.
Table 1.
Seroprevalence of T. gondii infection in domestic rabbits in Henan province, central China.
| Variable | No. examined | No. positive | Prevalence (%) | X2 | p-value |
|---|---|---|---|---|---|
| Region | |||||
| Anyang | 165 | 14 | 8.48 | 5.383 | 0.496 |
| Sanmenxia | 157 | 12 | 7.64 | ||
| Luoyang | 192 | 27 | 14.06 | ||
| Xuchang | 169 | 18 | 10.65 | ||
| Zhoukou | 176 | 21 | 11.93 | ||
| Zhumadian | 183 | 17 | 9.29 | ||
| Xinyang | 171 | 19 | 11.11 | ||
| Species | |||||
| Japanese White rabbit | 189 | 20 | 10.58 | 1.983 | 0.576 |
| Rex rabbit | 447 | 41 | 9.17 | ||
| New Zealand rabbit | 316 | 39 | 12.34 | ||
| Chinese rabbit | 261 | 28 | 10.73 | ||
| Gender | |||||
| Male | 534 | 61 | 11.42 | 0.767 | 0.381 |
| Female | 679 | 67 | 9.87 | ||
| Age (months) | |||||
| ≤6 | 316 | 21 | 6.65 | 14.361 | 0.001 |
| 6∼12 | 692 | 72 | 10.40 | ||
| ≥12 | 205 | 35 | 17.07 | ||
| Food | |||||
| Feed | 488 | 33 | 6.76 | 17.445 | < 0.001 |
| Fruits/vegetables/grains | 319 | 51 | 15.99 | ||
| Mixed* | 406 | 44 | 10.84 | ||
| Presence of cats | |||||
| Yes | 743 | 93 | 12.52 | 7.840 | 0.005 |
| No | 470 | 35 | 7.45 | ||
| Rearing system | |||||
| Commercial farms | 549 | 33 | 6.01 | 21.914 | < 0.001 |
| Household farms | 664 | 95 | 14.31 | ||
| Total | 1213 | 128 | 10.55 | ||
Mixture of feed and fruits, vegetables, and grains.
The rate of antibodies to T. gondii in male rabbits was 11.42% (61/534) and in female rabbits 9.87% (67/679) (Table 1). Although the seroprevalence in males was higher than the females, the difference was not significant (p>0.05). The prevalence of T. gondii infection in rabbits increased significantly (p < 0.01) with age. Rabbits no younger than twelve months exhibited the highest seroprevalence (17.07%), followed by rabbits of 6-12 months (10.40%), and then rabbits ≤ 6 months (6.65%) (Table 1).
The highest seroprevalence of T. gondii infection (15.99%) was found in rabbits fed with a mixture of fruits, vegetables or grains. The probability of rabbits being infected by T. gondii was increased by the presence of cats at the feeding farm compared to farms without cats (12.52% vs 7.45%, p < 0.01). In terms of rearing systems, the T. gondii seroprevalence in rabbits raised on commercial farms (6.01%) was significantly lower than that of animals raised on household farms (14.31%, p < 0.01).
The univariate analyses on the correlation between serum positive rates of T. gondii and possible risk factors are shown in Table 1, indicating significant associations between serum positive rates of T. gondii and food type, rabbit ages, cat presence on feeding farms, as well as the rearing system.
Seroprevalence of E. cuniculi
As shown in Table 2, in total 235 (19.37%) rabbits were positive for anti-E. cuniculi antibodies. Rabbits with positive antibodies in serum were found at all tested sites, varying from 11.83% in Xuchang city to 29.55% in Zhoukou city (Table 2). Rex rabbits exhibited the highest value of serum positive rates in all studied species (24.16%), followed by New Zealand rabbits (17.41%), then Japanese White rabbits (16.93%), while the prevalence found in Chinese rabbits was 15.32%. The serum positive rate of female rabbits (21.50%) was remarkably higher than that of male rabbits (16.67%) (p < 0.05).
Table 2.
Seroprevalence of E. cuniculi infection in domestic rabbits in Henan province, central China.
| Variable | No. examined | No. positive | Prevalence (%) | X2 | p-value |
|---|---|---|---|---|---|
| Region | |||||
| Anyang | 165 | 31 | 18.79 | 28.003 | < 0.001 |
| Sanmenxia | 157 | 33 | 21.02 | ||
| Luoyang | 192 | 48 | 25.00 | ||
| Xuchang | 169 | 20 | 11.83 | ||
| Zhoukou | 176 | 52 | 29.55 | ||
| Zhumadian | 183 | 24 | 13.11 | ||
| Xinyang | 171 | 27 | 15.79 | ||
| Species | |||||
| Japanese White rabbit | 189 | 32 | 16.93 | 10.803 | 0.013 |
| Rex rabbit | 447 | 108 | 24.16 | ||
| New Zealand rabbit | 316 | 55 | 17.41 | ||
| Chinese rabbit | 261 | 40 | 15.32 | ||
| Gender | |||||
| Male | 534 | 89 | 16.67 | 4.475 | 0.034 |
| Female | 679 | 146 | 21.50 | ||
| Age (months) | |||||
| ≤6 | 316 | 39 | 12.34 | 24.159 | < 0.001 |
| 6∼12 | 692 | 135 | 19.51 | ||
| ≥12 | 205 | 61 | 29.76 | ||
| Food | |||||
| Feed | 488 | 56 | 11.48 | 36.364 | < 0.001 |
| Fruits/vegetables/grains | 319 | 89 | 27.89 | ||
| Mixed* | 406 | 90 | 22.17 | ||
| Rearing system | |||||
| Commercial farms | 549 | 71 | 12.93 | 26.636 | < 0.001 |
| Household farms | 664 | 164 | 24.70 | ||
| Total | 1213 | 235 | 19.37 | ||
Mixture of feed and fruits, vegetables, and grains.
Moreover, it was revealed by comparing infection rates by ages that 39/316 E. cuniculi seropositive animals (12.34%) were young (≤ 6 months), 135/692 (19.51%) were adults (6∼12 months), and 61/205 (29.76%) were in older age groups (≥ 12 months). The E. cuniculi seropositivity of rabbits increased significantly (p < 0.01) with the increase of rabbit’s age.
Like in T. gondii infection, the highest E. cuniculi seroprevalence (27.89%) was found in rabbits fed with a mixture of fruits, vegetables or grains. Moreover, E. cuniculi seroprevalence in rabbits raised on commercial farms was also significantly lower than that of animals raised on household farms (12.93% vs 24.70%, p < 0.01).
Co-infection with T. gondii and E. cuniculi
Among the 279 infected rabbits, co-infection with E. cuniculi and T. gondii was demonstrated in 84 specimens (30.11%). Forty-four rabbits (15.77%) were seropositive for T. gondii alone, while 151 rabbits (54.12%) were seropositive for E. cuniculi alone (Table 3).
Table 3.
Frequency of single infection and co-infection in all 279 infected rabbits.
| Infection | No. positive | Percentage (%) |
|---|---|---|
| T. gondii only | 44 | 15.77 |
| E. cuniculi only | 151 | 54.12 |
| Co-infection of T. gondii and E. cuniculi | 84 | 30.11 |
| Total | 279 | 100.00 |
Discussion
The current investigation showed that the total serum positive rate of T. gondii was 10.55% among domestic rabbits in Henan, central China, which was lower than that found in Shanghai (23.4%) [22], but higher than that observed in Liaoning (6.5%), Jilin (4.5%), Heilongjiang (3.7%), and the Inner Mongolia Autonomous Region (3.5%) [13] of China. Meanwhile, the serological results of this study revealed that the overall serum positive rate for E. cuniculi was 19.37% in domestic rabbits in Henan. In comparison to other provinces within China mainland, the serum positive rate of 19.37% was lower than the values of 22.2% among rabbits investigated previously in Inner Mongolia, 30.9% in Liaoning [13], and 41.0% in Jilin [15], but higher than that observed in Sichuan (9.0%), Chongqing (6.0%) [15], and Heilongjiang (17.3%) [13]. The variations of serum positive rates for anti-T. gondii and anti-E. cuniculi antibodies among different regions are probably attributable to different rabbit breeds, sample capacities, time of investigations, and testing methods, as well as geographical and ecological factors.
The serum positive rate for T. gondii in the current work was lower than that of E. cuniculi, which was consistent with previous literature reports [13,14]. The spreading of E. cuniculi among herds was remarkably promoted by directly transmitting spores from urine of affected animals [14].
In the present study, the highest seroprevalence of T. gondii was found in New Zealand rabbits, while Rex rabbits had the highest seroprevalence of E. cuniculi. Regarding the breed of rabbits, de Lima et al. [5] and Alvarado-Esquivel et al. [3] reported a higher seroprevalence of T. gondii in New Zealand rabbits than in other breeds. Pan et al. also revealed higher serum positive rates for E. cuniculi among Rex rabbits than those among New Zealand and Japanese White Rabbits (p < 0.01) [15]. These results indicate that there may be a potential association between the breed of rabbits and the seropositivity against T. gondii and E. cuniculi. Most epidemiological surveys indicated no association between T. gondii and E. cuniculi infection and gender of the animals [13,18,19]. In our study, the gender of rabbits was not a significant risk factor for the presence of infection with T. gondii, which was in agreement with many previous studies [5,18]. However, female rabbits exhibited remarkably higher seroprevalence for E. cuniculi in comparison to male animals of our study. The role of gender in the epidemiology of rabbit encephalitozoonosis requires further research.
Increasing age was confirmed as a risk factor for both T. gondii and E. cuniculi infection. The observed higher seroprevalence for both protists in older rabbits suggests that these infections are mainly maintained by horizontal rather than vertical transmission. This finding is in accordance with other similar surveys [13,17].
Rabbits fed with fruits, vegetables and grains had the highest serum positive rates of T. gondii and E. cuniculi according to the current study, which was consistent with other reports [3]. This might be because these foods had a higher level of contamination of T. gondii oocysts or E. cuniculi spores than feed or mixed food. Cats play an essential role in T. gondii spreading since they are the final hosts and shed oocysts into the environment [11,20]. In this study, the presence of cats on rabbit farms was confirmed as one of the risk factors for occurrence of T. gondii infection among rabbits, which accorded with findings in previous literature reports [5,9].
In terms of rearing systems, both T. gondii and E. cuniculi seroprevalence rates were significantly higher in rabbits raised on household farms than in those raised on commercial farms, which is probably due to lower hygiene standards on household farms. Our findings are similar to those of previous reports [12,14]. These results suggest that the rearing system is a very important risk factor associated with T. gondii infection in rabbits as well as E. cuniculi infection.
Conflict of interest statement
The authors declare that they have no conflicts of interest in relation to this article.
Acknowledgements
This work was supported by the National Natural Science Foundation of China (No. 81702025 & 31372407), the Doctoral Scientific Research Activation Foundation of Xinxiang Medical University (No. XYBSKYZZ201504 & XYBSKYZZ201631), and the support project for the Disciplinary group of Psychology and Neuroscience, Xinxiang Medical University (2016PN-KFKT-26).
Cite this article as: Wang S, Yao Z, Li L, Pan Y, Li P, Nan X, Xie Q, Zhang Z. 2018. Seroprevalence of Toxoplasma gondii and Encephalitozoon cuniculi among domestic rabbits in central China. Parasite 25, 9
References
- 1. Abu-Akkada SS, Ashmawy KI, Dweir AW. 2015. First detection of an ignored parasite, Encephalitozoon cuniculi, in different animal hosts in Egypt. Parasitology Research, 114(3), 843-850. [DOI] [PubMed] [Google Scholar]
- 2. Abu-Akkada SS, El Kerdany ED, Mady RF, Diab RG, Khedr GA, Ashmawy KI, Lotfy WM. 2015. Encephalitozoon cuniculi infection among immunocompromised and immunocompetent humans in Egypt. Iranian Journal of Parasitology, 10(4), 561-570. [PMC free article] [PubMed] [Google Scholar]
- 3. Alvarado-Esquivel C, Alvarado-Esquivel D, Villena I, Dubey JP. 2013. Seroprevalence of Toxoplasma gondii infection in domestic rabbits in Durango State, Mexico. Preventive Veterinary Medicine, 111(3-4), 325-8. [DOI] [PubMed] [Google Scholar]
- 4. Alvarado-Esquivel C, Torres-Berumen JL, Estrada-Martinez S, Liesenfeld O, Mercado-Suarez MF. 2011. Toxoplasma gondii infection and liver disease: a case-control study in a northern Mexican population. Parasites & Vectors, 4, 75. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 5. de Lima DC, Santos Ade S, da Silva LT, de Melo RP, da Silva JG, Junior JW, Mota RA. 2016. Occurrence of Toxoplasma gondii in domestic rabbits of Northeastern Brazil. Acta Parasitologica, 61(3), 500-507. [DOI] [PubMed] [Google Scholar]
- 6. Ditrich O, Chrdle A, Sak B, Chmelik V, Kubale J, Dykova I, Kvac M. 2011. Encephalitozoon cuniculi genotype I as a causative agent of brain abscess in an immunocompetent patient. Journal of Clinical Microbiology, 49 (7), 2769-2771. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 7. do Nascimento LC, Pena HFJ, Leite Filho RV, Argenta FF, Alves BF, Oliveira S, Gennari SM, Driemeier D. 2017. Rare case of acute toxoplasmosis in a domestic rabbit (Oryctolagus cuniculus) in Brazil associated with the type BrIII Brazilian clonal lineage of Toxoplasma gondii. Parasitology Research, 116(10), 2873-2876. [DOI] [PubMed] [Google Scholar]
- 8. Dubey JP. 2010. Toxoplasmosis of animals and humans: CRC Press; 313 pp. [Google Scholar]
- 9. Elez RMMA, Hassanen EAA, Tolba HMN, Elsohaby I. 2017. Seroprevalence and risk factors associated with Toxoplasma gondii infection in domestic rabbits and humans. Veterinary Parasitology Regional Studies & Reports, 8, 133-137. [DOI] [PubMed] [Google Scholar]
- 10. Hill DE, Chirukandoth S, Dubey JP. 2005. Biology and epidemiology of Toxoplasma gondii in man and animals. Animal Health Research Reviews, 6(1), 41-61. [DOI] [PubMed] [Google Scholar]
- 11. Lilly EL, Wortham CD. 2013. High prevalence of Toxoplasma gondii oocyst shedding in stray and pet cats (Felis catus) in Virginia, United States. Parasites & Vectors, 6, 266. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 12. Maestrini G, Ricci E, Cantile C, Mannella R, Mancianti F, Paci G, D’Ascenzi C, Perrucci S. 2017. Encephalitozoon cuniculi in rabbits: Serological screening and histopathological findings. Comparative Immunology, Microbiology and Infectious Diseases, 50, 54-57. [DOI] [PubMed] [Google Scholar]
- 13. Meng QF, Wang WL, Ni XT, Li HB, Yao GZ, Sun XL, Wang WL, Cong W. 2015. Seroprevalence of Encephalitozoon cuniculi and Toxoplasma gondii in domestic rabbits (Oryctolagus cuniculus) in China. Korean Journal of Parasitology, 53(6), 759-763. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 14. Neumayerova H, Jurankova J, Jeklova E, Kudlackova H, Faldyna M, Kovarcik K, Janova E, Koudela B. 2014. Seroprevalence of Toxoplasma gondii and Encephalitozoon cuniculi in rabbits from different farming systems. Veterinary Parasitology, 204(3-4), 184-190. [DOI] [PubMed] [Google Scholar]
- 15. Pan Y, Wang S, Liu X, Li R, Sun Y, Gadahi JA. 2015. Seroprevalence of Encephalitozoon cuniculi in humans and rabbits in China. Iranian Journal of Parasitology, 10(2), 290-295. [PMC free article] [PubMed] [Google Scholar]
- 16. Rodriguez-Tovar LE, Villarreal-Marroquin A, Nevarez-Garza AM, Castillo-Velazquez U, Rodriguez-Ramirez HG, Navarro-Soto MC, Zarate-Ramos JJ, Hernandez-Vidal G, Trejo-Chavez A. 2017. Histochemical study of Encephalitozoon cuniculi spores in the kidneys of naturally infected New Zealand rabbits. Journal of Veterinary Diagnostic Investigation, 29(3), 269-277. [DOI] [PubMed] [Google Scholar]
- 17. Santaniello A, Dipineto L, Rinaldi L, Menna LF, Cringoli G, Fioretti A. 2009. Serological survey of Encephalitozoon cuniculi in farm rabbits in Italy. Research in Veterinary Science, 87(1), 67-69. [DOI] [PubMed] [Google Scholar]
- 18. Shin HG, Lee SE, Hong SH, Kim SM, Choi YK, Park HJ, Seo KW, Song KH. 2013. Prevalence of Toxoplasma gondii infection in rabbits of Korea by serological tests and nested polymerase chain reaction. Journal of Veterinary Medical Science, 75(12), 1609-1613. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 19. Shin JC, Kim DG, Kim SH, Kim S, Song KH. 2014. Seroprevalence of Encephalitozoon cuniculi in pet rabbits in Korea. Korean Journal of Parasitology, 52(3), 321-323. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 20. Wang S, Zhou Y, Niu J, Xie Q, Xiao T, Chen Y, Li H, Ma C, Zhang H, Liu S, Zhang Z. 2017. Seroprevalence of Toxoplasma gondii infection in domestic cats in central China. Parasite, 24, 10. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 21. Zhang N, Wang S, Wang D, Li C, Zhang Z, Yao Z, Li T, Xie Q, Liu S, Zhang H. 2016. Seroprevalence of Toxoplasma gondii infection and risk factors in domestic sheep in Henan province, central China. Parasite, 23, 53. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 22. Zhou Y, Zhang H, Cao J, Gong H, Zhou J. 2013. Isolation and genotyping of Toxoplasma gondii from domestic rabbits in China to reveal the prevalence of type III strains. Veterinary Parasitology, 193(1-3), 270-276. [DOI] [PubMed] [Google Scholar]