Oslerus rostratus (Gerichter, 1949) Anderson, 1978

This is a metastrongyloid nematode parasite of felines that occasionally finds its way into the domestic cat. Oslerus rostratus is a large worm that is closely related to the canine parasite Oslerus (= Filaroides) osleri; some workers consider the genus Anafilaroides containing the genus rostratus to be distinct from the genus Oslerus (e.g., Seneviratna (1959). Oslerusrostratus has been reported from cats in the United States, Pacific Islands, Southern Europe,and the Middle East (Gerichter, 1949; Ash, 1962; Seneviratna, 1959; Juste et al., 1992). The adult males are about 28-37 mm long, and the adult females are 48-64 mm long. The worms are typically found in the bronchial submucosa. The vulva in the female is located just anteriad to the anus. The larvae found in the feces are 335 to 412 um long and have a tail that is similar to that of Oslerus osleri. The life cycle has been described by Gerichter (1949) and Klewer (1958) who found that the larvae were capable of development in slugs. Seneviratna (1959) has shown that the third-stage larvae from slugs are capable of infecting mice that serve as paratenic hosts. Similarly, he found that week-old chickens could be infected as paratenic hosts and that the larvae recovered from these chicks were capable of infecting a cat. Larvae were first observed in the cat 78 days after being given infective-stage larvae. There have been no studies on the signs of infection with this parasite or on effectiveness of different treatments.


Ash LR. 1962. Helminth parasites of dogs and cats in Hawaii. J Parasitol. 48:63-65.

Gerichter 1949. Studies on the nematodes parasitic in the lungs of felidae in Paelestine. Parasitology 39:251-262.

Klewer HL. 1958. The incidence of helminth lung parasites of Lynxrufusrufus (Schabes) and the life cycle of Anafilaroides rostratus (Gerichter). J Parasitol 44:29.

Seneviratna P. 1959. Studies on Anafilaroides rostratus Gerichter, 1949 in cats. II. The life cycle. J Helminthol 33:109-122.

Senebiratna P. 1959. Studies on the family Filaroididae Schulz, 1951. J Helmintol 33:123-144.

Juste RA, Garcia AL. Mecia L. 1992. Mixed infestation of a domestic cat by Aelurostrongylusabstrusus and Oslerusrostratus. Ang Parasitol 33:56-60.