Praziquantel treatment for Platynosomum species infection of a domestic cat on St Kitts, West Indies

Abstract

Case summaryA 1-year-old, female spayed, domestic shorthair, indoor cat on the island of St Kitts was diagnosed with platynosomiasis, infection with a feline-specific liver fluke, and treated with praziquantel at the marketed dose for tapeworms (5 mg/kg; actual calculated dose 5.75 mg/kg). Serial fecal analyses showed that egg counts decreased to zero within 10 days of treatment but re-emerged at day 17 and persisted at low levels until a second treatment was administered on day 78. After the second treatment, all fecal samples (n = 15) from day 85 to day 350 post-initial treatment were negative for Platynosomum ova.Relevance and novel informationTreatment of platynosomiasis is poorly documented; no drugs are labeled for use against Platynosomum and the efficacy of suggested treatments is unknown. Using 5.75 mg/kg once, a dose that is significantly lower than published recommended doses for platynosomiasis, egg counts initially disappeared but re-emerged and persisted at low levels until a second treatment was administered. We hypothesize that immature forms may not have been killed and subsequently matured to produce eggs, or that the one-time dose may not have been completely effective at eliminating all adult flukes. However, administering praziquantel at 5.75 mg/kg twice, several weeks apart, appeared to be effective in treating this cat with platynosomiasis, as evidenced by monitoring of fecal egg counts over the course of 350 days.

Treatment of primate platynosomosis: A word of caution about the use of praziquantel in marmosets

“…In feline platynosomosis, different treatment schedules and dosages of PZQ have been adopted. For example, doses of 20 mg/kg BW once a day for three to five consecutive days were used by different authors 12‐14,16,28 . In most studies, monitoring of efficacy through qualitative analysis of parasite eggs in feces was performed, but quantitative evaluation was not considered.…”

“…For example, doses of 20 mg/kg BW once a day for three to five consecutive days were used by different authors. [12][13][14]16,28 In most studies, monitoring of efficacy through qualitative analysis of parasite eggs in feces was performed, The data obtained raise a dilemma regarding the use of PZQ in the treatment of platynosomosis. If, on the one hand, the drug is effective against the fluke, on the other hand, at least under the conditions studied, the risk of complications for the host, including death, cannot be negligible.…”

“…In fact, the drugs already used in the treatment of platynosomosis in non‐human primates were empirically adopted 6,10 . There are reports of drug efficacy, particularly of praziquantel (PZQ), in cats infected with this fluke 11‐13 . However, the efficacy and potential complications of some treatment schedules are not completely known, since the drugs that have been used, including PZQ, their dosage and efficacy are varied 11‐16 …”

“…In our study, there was also a marked reduction in the mean number of fluke eggs in the feces of marmosets after treatment, which indicates the effectiveness of PZQ against P. illiciens.The data obtained suggest that the therapeutic regimen used probably did not quickly eliminate all worms in the primates, since some specimens again shed eggs in their feces after having the firstnegative results. Similar findings were previously observed in feline platynosomosis, and in addition to the rationale that the drug may not have been completely effective at eliminating all adult flukes, the following alternative explanations (not mutually excluding) for this observation have been suggested: (a) inadequate dose or posology may have been used; (b) immature worms may not have been killed and subsequently matured and produce eggs; and (c) sequestration of fluke eggs in the bile ducts of the host [11][12][13][14]. In addition, a higher proportion of unembryonated eggs was observed in the feces of marmosets after treatment.…”

Efficacy of Praziquantel in the Treatment of Platynosomum fastosum in Cats with Natural Infections

“…In both studies, fecal egg counts were used to evaluate efficacy. In a recent case study, a lower dose of praziquantel (5.7 mg/kg BW) administered twice several weeks apart was found to be effective, suggesting that the treatment interval might be as important as the dose [ 8 ]. In the study reported here, post mortem fluke counts vs. fecal egg counts were used to assess the efficacy of praziquantel at the dose of 20 mg/kg BW daily for three days.…”