Feline trypanosomosis in a free-ranging domestic shorthair cat (Felis catus)

Introduction

Hematophagous vectors such as Stomoxys, Tabanus, and Triatomine bugs are the primary transmitters of trypanosomosis. Recent evidence also suggests transmission via the ingestion of carcasses from recently infected animals, broadening the understanding of potential infection routes [4,11,13,17] . Trypanosoma infections are widespread, ranging from Africa and Asia to the Americas [17] . Clinical manifestations range from acute febrile episodes, hyperthermia, anorexia, anaemia, and lethargy to chronic wasting, lymphadenopathy, and neurological signs such as encephalitis, seizures, and ataxia [1,3,12,15,16] . Peripheral blood smears from the ear vein are used to identify blood parasites such as Trypanosoma spp. [3] . Diagnosis is confirmed via microscopic detection of trypanosomes in Giemsa-stained thick and thin blood smears, PCR, ELISA, immunofluorescent tests, or cerebrospinal fluid (CSF) analysis for patients with central nervous system involvement [3,17] . Molecular and immunological diagnostic techniques are generally used to identify the causative species in an infection [5,6,9,10] . Treatment involves the administration of trypanocides (or chemotherapeutic drugs), such as dimidium bromide, potassium antimony tartrate, suramin, melarsamine, quinapyramine, homidium, diminazene aceturate, and isometamidium, of which the latter six may also be used as prophylactic drugs [2,7,17] . Prophylactic drugs and chemotherapeutic drugs have no fundamental difference, except that the ones used in chemoprophylaxis show a longer curative concentration in the body (three months) than the rest [17,[99][100][101] . Resistance to homidium is prevalent [17,[99][100][101] . The subcutaneous route of injection may cause skin necrosis and pain due to local irritation, the intravenous route may cause necrosis of vessel walls, often causing fatality, whereas the intramuscular route causes no such damage and significantly less pain [17, pp. 90-94] . Vaccination attempts against trypanosomosis have failed, making vector control and chemoprophylaxis the only reliable preventative measures [17, .

The incidence of naturally occurring trypanosomosis in felines has rarely been reported in the scientific literature, primarily because cats are relatively more resistant than other vertebrate hosts are. As a result, trypanosomosis is rarely observed and diagnosed in felids, rendering it an uncommon parasitic infection within this species [8] . Feline trypanosomosis in domestic cats has been reported in one case in India [14] , one case in Canada [8] , three cases in Kuwait [15] , and seven cases in Iraq [9] . The infections were caused by Trypanosoma brucei and Trypanosoma evansi [4,8,9,14,15] , both of which elicit the same clinical symptoms in cats, which are directly proportional to parasitaemia.

Patient Information:

An adult (~6 years old), female, free-ranging domestic short hair came in with the complaint of alopecia several weeks after spay surgery, limping, loss of condition, and polydipsia. She was referred to multiple clinics where various tests and treatments were carried out before she came in for an appointment at our clinic.

History

Treatment

The treatment plan included administration of Diminazene Aceturate (Berenil® Vet 7% RTU) at the dose rate of 3.5 mg/kg deep i/m once a week for 4 weeks, along with buprenorphine (Bupren) at a dose rate of 0.02 mg/kg and fluids (DNS and RL) at 30 ml/kg body weight. The course of doxycycline prescribed on 29/07/2024 continued to be completed.

The first dose was administered on 03/08/2024, after which her appetite increased and her hair began growing at the site of alopoecia. No adverse reactions were noted. Decubitus ulcers were found at the hock joints bilaterally due to her plantigrade posture, caused by a lack of muscle tone and overall body strength. An increase in incoordination was noted due to a further reduction in muscle mass, presumably due to immobility caused by her being fostered under a facility where she was kept in a cage. Syrup SAMe-Liv (Sadenosylmethionine and A+B) was prescribed at 1.5 ml twice a day for 30 days. The second, third and fourth doses were administered on 09/08/2024, 16/08/2024 and 22/08/2024, respectively. Ointment Scavon (Himalaya) was prescribed for the decubitus ulcers. Ondansetron at 0.2 mg/kg was administered intravenously to avoid nausea caused by travel to and from the clinic. Blood tests performed on 12/08/2024 revealed mild infection and inflammation, among other non-appreciable findings.

A peripheral blood smear done on 22/08/2024 revealed no presence of parasites. She was diagnosed with Trypanosoma evansi infection via FNAC and PCR. The treatment plan included the use of diminazene aceturate (Berenil® Vet 7% RTU) [2,7,17] at a dosage of 3.5 mg/kg deep i/m [17] once a week for four weeks. Supplemental syrups and tonics were prescribed simultaneously. After two sessions of treatment, her appetite increased, and the patches of alopecia started showing new hair growth (Figure 3 c). Conjunctivitis and chemosis, along with the bilateral periocular oedema, were significantly reduced. Two weeks after the final dose, the decubital ulcers that formed due to cage rest and the plantigrade posture had healed, and her clinical signs disappeared (Figure 3 d). A complete blood panel was run on 24/10/2024 (Figure 4), which revealed all values to be within the normal range. The cat was released into her surroundings since she was anxious about being indoors.

Conflict of Interest Not available

Financial Support

References

1. Dakshinkar NP, Dhoot VM, Upadhye SV, Bhojne GR, Sarode DB, Kolte SW. Trypanasomiasis in a jungle cat. Indian Vet J. 2002;79(1):66-67.
2. DaSilva AS, Zanette RA, Wolkmer P, Costa MM, Garcia HA, Lopes ST, et al. Diminazene aceturate in the control of Trypanosoma evansi infection in cats. Vet Parasitol. 2009;165(1-2):47-50.
3. Desquesnes M. Surra in all species (Trypanosoma evansi infection). In: Terrestrial Manual 2021, by WOAH, 2021.
4. Desquesnes M, Holzmuller P, Lai D, Dargantes A, Lun Z, Jittaplapong S. Trypanosoma evansi and surra: A review and perspectives on origin, history, distribution, taxonomy, morphology, hosts, and pathogenic effects. BioMed Res Int. 2013;2013:194176. DOI: 10.1155/2013/194176.
5. Gaithuma AK, Yamagishi J, Martinelli A, Hayashida K, Kawai N, Marsela M, et al. A single test approach for acute and sensitive detection and taxonomic characterization of Trypanosomes by comprehensive analysis of internal transcribed spacer-1 amplicons. PLoS Negl Trop Dis. 2019;13(2):e0006842.
6. Gaur RS, Shanker D, Sudan V, Singh S, Jadaun A. Associative diversity of ITS-1 gene in different Trypanosoma evansi isolates of equine origin from SemiArid India. J Anim Res. 2021;11(4):755-60.
7. Giordani F, Morrison LJ, Rowan TG, Koning HP, Barrett MP. The animal trypanosomiases and their chemotherapy: A review. Parasitology. 2016;143(14):1862-89.
8. Hill DH. Trypanosoma brucei in the cat. Br Vet J. 1955;1112:77-80.
9. Mohammed NH, Moosa DA, Altaliby MAM. Diagnostic study of trypanosomiasis of cats in Mosul, Iraq. Open Vet J. 2022;12(5):688-92. DOI: 10.5455/OVJ.2022.v12.i5.13.
10. Mulenga GM, Gummow B. The detection of African trypanosomes in goats reared in tsetse-infested villages of Eastern Zambia. Trop Anim Health Prod. 2022;54(6):370.
11. Nwoha RIO. A review on trypanosomosis in dogs and cats. Afr J Biotechnol. 2013;12(26):6432-6433. DOI: 10.5897/AJB2013.12093.
12. Paikne DL, Dhake PD. Trypanosomiasis in a domestic cat (Felis catus). Indian Vet J, 1974.
13. Raina AK, Kumar R, Rajora VS, Sridhar, Singh RP. Oral transmission of Trypanosoma evansi infection in dogs and mice. Vet Parasitol. 1985;18(1):67-69.
14. Shivajothi S, Reddy BS. Trypanosoma evansi infection in cat -a rare case. Comp Clin Pathol. 2018;27(1):115-116. DOI: 10.1007/s00580-017-2560-x.
15. Tarello W. Trypanosoma evansi infection in three cats. Rev Med Vet. 2015;156(3):133-4.
16. Thirunavukkarasu PS, George RRS, Nambi AP, Ramesh S, Vasu K. Trypanomiosis in a cat -a clinical report. Indian Vet J. 2000;77:428-429.
17. Uilenberg G. A field guide for the diagnosis, treatment and prevention of African animal trypanosomosis. Rome: Food and Agriculture Organization of the United Nations, 1998.