SUSPECTED CLINICAL TOXOPLASMOSIS IN PET RABBITS ( ORYCTOLAGUS IN LIMA, PERU

: Toxoplasmosis is a prevalent disease among rabbits in many areas of the world. However, its clinical presentation is very uncommon. In South America, prevalence of toxoplasmosis in rabbits is unknown and clinical reports on this disease are scarce or inexistent. Antibodies against Toxoplasma gondii were found in four pet rabbits, which were received at the Wild and Exotic Animals´ Clinic, School of Veterinary Medicine, Universidad Nacional Mayor de San Marcos (Lima, Peru). These animals were received over about one year and belonged to different owners. The most common reasons for presentation were anorexia/hyporexia and difficulty to walk. The most frequently observed clinical sign was myalgia. All rabbits presented anemia, lymphopenia, and increased creatinine. The 75% (3/4) of patients died or were humanely euthanized. This article describes the presence of antibodies against T. gondii in clinically ill rabbits for the first time in Peru. Based on these observations, research on prevalence of toxoplasmosis in rabbits and its associated risk factors are recommended.


INTRODUCTION
Toxoplasmosis is among the most common zoonotic diseases worldwide (it is present in about 30 to 50% of world population); and it is also considered an important opportunistic infection in immunocompromised patients (Torrey and Yolken, 2003;Barakat, 2007;Dubey and Jones, 2008;Muñoz-Zanzi et al., 2010;Flegr et al., 2014). The etiologic agent is Toxoplasma gondii, an obligate intracellular protozoan first described in 1908 by Nicolle and Manceaux in USA and by Splendore in Brazil (Black and Boothroyd, 2000;Barakat, 2007;Cenci-Goga et al., 2011). This parasite infects the intestine of domestic and wild felids, which are its definitive host (Méndez et al., 2011). Most birds (recorded in more than 30 species) and mammals (recorded in more than 300 species) are potential intermediate hosts. Australian marsupials, arboreal primates and lemurs are highly susceptible (Bowman et al., 2002;Almería et al., 2004;Flegr et al., 2014;Carlson-Bremer et al., 2015). Moreover, T. gondii has recently been detected in snakes, being the first record of natural infection by this parasite in reptiles (Nasiri et al., 2016).
Toxoplasmosis in rabbits has three presentations: latent infection (i.e. asymptomatic, commonly seen in immunocompetent adult rabbits), chronic infection (i.e. old rabbits presenting cyst in muscles and nervous tissue, with intermittent episodes of clinical disease which are associated to immunosuppression and stress), and acute infection (i.e. commonly seen in young rabbits, which die in about 2 to 8 days post infection) (van Praag, 2014). Clinical signs are frequently observed in acute episodes of disease, among them are described: anorexia, pyrexia, ataxia, hind limbs paresis, tetraplegia, seizures, and death (Fisher and Carpenter, 2012;Varga, 2014). Survival rates are very low and prognosis is poor due to the sudden and quick progression of parasitosis (van Praag, 2014).
Information related to clinical cases of toxoplasmosis in rabbits is scarce in South America and practically non-existent in Peru. This article describes the clinical presentation, clinicopathological findings, and therapeutics in pet rabbits presenting clinical manifestation suggesting toxoplasmosis and showing antibodies against T. gondii.

Review of clinical records
A systematic review of clinical records of pet rabbits received from

Statistical Analysis
Mean, standard deviation, and range were estimated for age and survival time data. Sex, clinical signs, hematological findings, and biochemical findings were summarized using frequencies.

RESULTS
A total of 255 clinical records were reviewed, in which four cases of rabbits with clinical diagnosis of suspected toxoplasmosis were found. Hence, frequency of suspected clinical toxoplasmosis in rabbits received at our clinic during 2015 was 1,6% (CI95% 0,4 -4,0%). Clinical data of these rabbits are presented in Table 1. Mean age of rabbits with toxoplasmosis was 5,25 ± 1,5 (range 4-7) years and 75% (3/4) were female. Survival time (from clinical signs presentation to death or humane euthanasia) was 6,7 ± 1,2 (range 1-7) days and only in one of the four cases the patient recovered from illness. The only recovered rabbit was treated during 6 weeks, until clinical signs disappeared and antibodies against T. gondii were not detected. Such animal was rechecked 6 months later and was found clinically healthy but in poor body condition. Table  1.
Clinical, hematological, and biochemical data of rabbits presenting antibodies against T. gondii.
All rabbits presented anemia and lymphopenia.

DISCUSSION
To the authors´ knowledge, this article reports the presence of antibodies against Toxoplasma gondii in clinically ill pet rabbits (Oryctolagus cuniculus) in Peru for the first time. Previous research in Peru has reported the presence of antibodies against T. gondii in other domestic animal species such as in dog (Canis lupus familiaris), sheep (Ovis aries), pig (Sus scrofa), llama (Lama glama), alpaca (Vicugna pacos), and cat (Felis catus) (Suárez-Aranda et al., 2000;Ruíz et al., 2012;Angulo et al., 2014;Cerro et al., 2014;Chávez-Velásquez et al., 2014;Pinedo et al., 2014;Bernal et al., 2015). Moreover, toxoplasmosis is a prevalent disease in Peruvian human population (Maguiña et al., 2004). From a public health perspective, it should be highlighted that people handling or eating raw or undercooked meat from infected rabbits might get toxoplasmosis (Lennox and Kelleher, 2009;Varga, 2014). Hence, based on our findings it is strongly recommended to assess the prevalence of T. gondii in rabbits bred for human consumption. Furthermore, as other small mammals (e.g. hedgehogs, ferrets, guinea pigs, pot-bellied pigs, sugar gliders) kept as exotic pets are susceptible to toxoplasmosis, this disease should be considered among differential diagnosis for such species.
The observed prevalence of clinical toxoplasmosis reported in this study agrees with Dubey et al. (1992) who signaled such kind of presentation in rabbits is considered rare. Despite the diagnostic test kit used in the described cases has not specifically been validated for rabbits, the same technique (i.e. Indirect Hemagglutination) has previously been employed in lagomorphs (e.g. rabbits and hares) (Ahmmed et al., 2011;Luo et al., 2017). The seropositive rabbits analyzed did not live with cats and all of them were fed diets including fresh vegetables. Based on this, the most likely source of infection is postulated to be the ingestion of vegetables contaminated with cat feces containing T. gondii oocysts, as suggested by Dubey et al. (1992). All seropositive rabbits were adult or aged animals. According to what is described by van Praag (2014), such animals may have been chronically infected with toxoplasmosis and presented with an acute episode, potentially due to stress or immunosuppression associated with disease or aging. Active infection (expressed by the detection of IgM) was diagnosed only in one patient. Most patients were female, but association between disease and gender was not statistically assessed due to the limited sample size. In most presented cases, clinical disease progressed to death or humane euthanasia of animals, due to poor prognosis and lack of therapeutic success. Mean survival time was less than one week. These findings agree with the high mortality rate and poor prognosis described by van Praag (2014) for acute toxoplasmosis. Unfortunately, post mortem examination was not authorized in any case. Consequently, a definitive diagnosis of toxoplasmosis could not be fully established by means of highly sensitive and specific techniques such as histopathology and PCR.
With regard to increased creatinine, van Praag (2014) has described it as commonly recorded in rabbits with toxoplasmosis. However, it should not be considered a main characteristic of this disease. The most frequent reason for patient consultation was difficulty for walking (2/4), whereas the most commonly found clinical sign was myalgia (diagnosed by palpation of forelimb and hindlimb muscles and observation of response suggesting pain) (4/4). Hyperthermia and hypothermia were observed in 50% and 25% of toxoplasmosis cases, respectively; and poor body condition was recorded in 75% of patients. Based on clinical presentation of paresis and poor body condition, encephalitozoonosis (a disease previously reported in rabbits in Lima, Peru) should be considered as a differential diagnosis (Chilón, 2014;van Praag, 2014). However, diagnostic test for encephalitozoonosis is not currently available in Peru. Additionally, in two cases vertebral alterations were detected which may explain the development of paresis but not hyperthermia and other observed clinical signs. Finally, constipation observed in one of the patients (i.e. Case 4) might be associated to pain as suggested by Meredith (2008), and this would have worsened the health status of the animal leading to its death.

CONCLUSIONS
For the first time in Peru, antibodies against T. gondii were detected in rabbits (Oryctolagus cuniculus) presenting clinical signs suggesting toxoplasmosis. Further studies regarding the seroprevalence of toxoplasmosis in rabbits in Peru are required for a better understanding of its epidemiology and potential risk to human health.
The authors certify that they have no affiliations with or involvement in any organization or entity with any financial or non-financial interest in the subject matter or materials discussed in this manuscript.