Pearsonema feliscati (Diesing, 1851) Freitas and Mendonça (1960)
ETYMOLOGY: Named for Dr. Pearson and felis-cat for the feline host.
SYNONYMS: Moravec (1982) accepted the species Pearsonemafeliscati as being distinct from Pearsonemaplica. After a long discussion of the history of the two species and their associated taxonomy, Butterworth and Beverly-Burton (1980), felt that the species in North American domestic cats should be considered as Capillariatravassoi (Freitas & Lent, 1936) Ehrlich, 1947. Butterworth and Beverley-Burton described the only reliable means of distinguishing the two species as patterns on the surfaces of the respective egg shells, appearing as large depressions and ridges on Pearsonemaplica and appearing striated on Capillariatravassoi, and by the terminal caudal alae of the males, triangular in Pearsonemaplica and rounded in Capillariatravassoi. Thus, until such time as these worms are more carefully compared and the eggs in the urine of cats more carefully studied and illustrated, it will be difficult to determine whether these are indeed the same species and whether or not their geographical ranges overlap.
HISTORY: In 1819 Rudolphi was the first to report the presence of nematode worms in the urinary bladder and renal pelvis in dogs, cats, and foxes. He named the parasite Capillariaplica. In 1851, Diesing identified a species of Capillaria in the bladder of cats from Egypt and other locales and named it Capillariafeliscati (Wilson-Hanson and Prescott, 1982a). Lewis (1927) reported this capillarid from the urinary bladder of cats in Wales. Chen (1934) recorded it from cats in Canton, China. Enzie (1951) felt that Pearsonemaplica was markedly different from the Pearonsmefeliscati usually encountered in feline urine and questions whether Pearsonema plica actually occurs in the cat. In 1953, Chitwood and Enzie published a report on Pearsonemaplica in the urinary bladder of a cat, adding further credence to the fact that the two species are distinct.
GEOGRAPHIC DISTRIBUTION:Pearsonemafeliscati has been observed in cats from localities throughout the world. Subsequent to its original documentation in Egyptian cats by Diesing, Lewis (1927) reported this capillarid from the urinary bladder of cats in Wales, and Finnerup (1986) reported it in a cat from Denmark. Chen (1934) recorded it from cats in Canton, China. Waddell (1967, 1968a) has reported infection rates in 34% and 31% of adult cats in Brisbane, Australia. A 12-month, Australian survey of 400 cats of varying ages revealed that 18.3% of cats aged 2 years and older were infected with Pearsonemafeliscati. Younger cats demonstrated a lower infection rate. No cat under 2 years of age was infected (Wilson-Hanson and Prescott, 1982b). In North America, Pearsonemafeliscati is either uncommon or overlooked (Lautenslager, 1976). Nevertheless, the occurrence of the feline bladder worm has been documented by veterinarians in the United States (Harris, 1981; Laketa, personal communication).
LOCATION IN HOST: Adult Pearsonemafeliscati are found within the urinary bladder of the cat. One source states that these worms move freely within the urine in the bladder and tend not to attach to the bladder mucosa. (Wilson-Hanson and Prescott, 1982a). Another source states that the tiny adult worms are embedded in the bladder epithelium. In some cases, the worms have been found in the ureters and the renal pelvis (Campbell, 1991).
IDENTIFICATION: Male Pearsonemafeliscati are 13 to 30 mm in length while the females are from 28 to 32 mm in length. The spicule sheath of the male, like that of species of Aonchotheca, is not spined. The labia of the female's vulva are slightly protruding; they are located some distance from the termination of the esophagus. Both sexes possess a terminal anus that is surrounded by three slight lobes (Enzie, 1951).
The eggs of this parasite are passed in the urine. The eggs of Peasonemafeliscati have been illustrated by Enzie (1951), Waddell (1967) and Burgu & Do?anay (1986). The eggs with bipolar plugs tend to have a pitted surface, but the surface does not, appear to have pits as large as those illustrated for Pearsonemaplica by Enzie (1951) and Butterworth & Beverley-Burton (1980). As shown by Enzie (1951) the eggs of Pearsonemafeliscati are markedly different than those of Pearsonema plica. When passed in the urine, the eggs typically contain one or two cells, and they measure 51 to 65 by 24 to 32 μm (Enzie, 1951) (Fig. 4-60).
LIFE CYCLE: The life cycle of Pearsonemafeliscati is thought to be similar to that of Pearsonemaplica as described by Enigk (1950) After passage in the urine, the eggs embryonate and after ingestion by earthworms, the larvae develop to the infective stage within the coelomic cavity. In the case of Pearsonemaplica, the earthworm is considered an obligate intermediate host. Following ingestion of infected earthworms by the final host, the larvae are found in the wall of the small intestine for the first 8 to 10 days after infection and then supposedly make their way via the circulatory system to the bladder. The prepatent period in experimentally infected foxes was 58 to 63 days.
Cats are not known to eat earthworms, and paratenic hosts (transport hosts), e.g., birds, have been suggested as the means by which cats become infected (Prescott, 1984). Some believe that the life cycle is direct, not involving an intermediate host.
CLINICAL PRESENTATION AND PATHOGENESIS:Pearsonemafeliscati is generally regarded as producing little pathology (Waddell, 1967, 1968a). However, if the ureters become plugged with worms, cats may display the clinical signs of post-renal obstruction (Campbell, 1991). In many infected cats, the serosal surface of the bladder is discolored a brownish-pink. This discoloration was observed in bladders containing 4 or more nematodes. The mucous membranes were not visibly inflamed; however in histopathologic section, there were areas of dilated blood vessels, extravasated blood and lifting transitional epithelium with some inflammatory cells. Within the incised bladders, all worms moved freely within the urine; none appeared to be attached to the bladder mucosa. The maximum number of adult worms recovered from a single urinary bladder was 25. Large numbers of eggs were found in all bladders containing 5 or more adults. Protein concentration of the urine increased as the adult population of Pearsonemafeliscati increased. There was no relationship between the presence of adult capillarids in the bladder and cystitis (Wilson-Hanson and Prescott, 1982a).
TREATMENT: Urinary capillariasis has been treated with oral methyridine (200 mg/kg, once). Transitory side effects were noted. Appetite was normal within 12 hours following treatment (Waddell, 1968b, Georgi, 1975).
Harris (1981) noted the disappearance of Pearsonema eggs from the urine of a cat following treatment with levamisole (45 mg, SC, once a week for 2 injections). Ivermectin (0.2 mg/kg. SC) has been reported to be successful in treating urinary capillariasis in a dog (Kirkpatrick and Nelson, 1987).
EPIZOOTIOLOGY: Older cats may serve as carriers. The exact role of wild animals in the epizootiology of urinary capillariasis is not known.
HAZARDS TO OTHER ANIMALS: As stated above it is not clear whether this parasite has a direct life cycle or one utilizing an intermediate host. Thus, it is difficult to determine to what extent environemental contamination with eggs shed in the urine would be in a cattery situation.
HAZARDS TO HUMANS: There have been no documented cases of the transmission of Pearsonemafeliscati from cats to man.
CONTROL/PREVENTION: Methods of control include keeping animals away from soil surfaces and discouraging contact with areas frequented by wild animals (Campbell, 1991).
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Figure 4-60. Pearsonemafeliscati. Two views of the egg of this worm that are found in the urine. The view on the left shows the large punctate pits that appear to be within the eggshell, the view on the right shows the bleb-like striations on the surface of the shell.