Mammomonogamusierie (Buckley, 1934) Ryzhikov, 1948

ETYMOLOGY:Mammo (=mammal) and monogamus (for the finding of the worms in pairs of males and females); ierei for Dr. Iere.

SYNONYMS:Syngamusierei Buckley, 1934

HISTORY: This worm was first described by Buckley with specimens from domestic cats collected in Trinidad. Buckley differentiated this species from Mammomonogamusfelis, which was reported from the tiger (Cameron, 1931), on the basis of its lack of supporting ribs in the mouth capsule. Of the two major species in ruminants, Mammomogamusnasicola and Mammomonogamuslaryngeus, only Mammomonogamuslaryngeus is considered to have spicules (Macko et al., 1981). It has also been noted that for Mammomonogamuslaryngeus in Cuba that some specimens have reduced ribs in the buccal capsule. Thus, it is possible that Mammomonogamusierei is a synonym of this parasite of ruminants. When humans who are from or have traveled to the Caribbean Islands , Brazil, or South East Asia are infected with Mammomongamus, the species is typically considered to be Mammomonogamuslaryngeus.

GEOGRAPHIC LOCATION: This worm was initially reported from the island of Trinidad where 15 of 32 cats were infected. It was found in cats from various parts of the island including Port of Spain, St. Augustine, Manzanilla, and Mayaro (Buckley, 1934). It appears that this worm is also rather common in Puerto Rico where a survey revealed that 13 of 40 cats were infected with this parasite (Cuadrado et al., 1980).

LOCATION IN HOST: The worms are restricted to the nares and nasopharynx.

PARASITE IDENTIFICATION: The females are about 20 mm long; with the maximum length reported by Buckley being 23.8 mm. The males are 5 to 6.9 mm long and rather stocky in appearance. The worms are found with the bursa of the male attached at the level of the vulva of the female. There is a large buccal capsule that has eight large teeth at its base. There are no supporting ribs extending up the sides of the capsule. The vulva of the female is located approximate one-third of the body length behind the anterior end of the worm. The esophagus is about 1 tenth to one twentieth of the total body length and is large and muscular. The male has spicules that are subequal in length, the left spicule ranges from 36 to 47 µm in length and the right spicule ranges in length from 44 to 58 µm. Buckley distinguished Mammomonogamusierei from Mammomonogamusfelis on the basis that Mammomonogamusierei had no supporting ribs in the mouth capsule, generally smaller buccal capsules, and larger spicules.

The eggs of Mammomonogamusierei were illustrated by Buckley as being ovoid with a shell that is clear and marked with fine irregular transverse striations. The eggs averaged 49.5 (48-52) µm by 92 (84-100) µm. The eggs when passed in the feces are typically in a four to six celled stage. Cuadrado et al. (1980) reported that the eggs of Mammomonogamus were typically larger than those of Ancylostoma, had a thicker shell, and that the shell in a salt flotation preparation was typically found with attached debris.

LIFE CYCLE: There has not been a complete description of the life cycle of any of the species of Mammomonogamus. Species of the related avian genera, Cyathostoma and Syngamus, have been found to infect birds through the ingestion of their embryonated eggs, free larvae, or the ingestion of earthworm paratenic hosts (Anderson, 1992). Also, it appears that Syngamustrachea can utilize other invertebrate paratenic hosts such as snails and slugs. Attempts to infect sheep with earthworms infected with Mammomonogamus nasicola or with free larvae of this parasite failed to induce infections with this parasite (Euzeby et al., 1977).

Buckley (1934) examined the development of the egg. At 26 to 30C, a first-stage larva appeared in 3 to 4 days. The second-stage larva appeared one to two days later. The third stage larva appears about 8 days after the culutres are established The hatched larva bears two sheaths, and is about 450 µm long and 16 µm wide. The posterior end of the esophagus is between one-third to one-half of the body from the anterior end. The anus is about 40 µm from the tip of the tail, and there is a small genital primordium at midbody. Buckley fed third-stage larvae two two cats and two kittens, but none of these cats developed patent infections over the next one and one-half months. Interestingly, fourteen days after this experiment was begun, one of the control cats began to pass eggs of Mammomonogamus. The fact that human cases have been reported in the USA in individuals within a week after their short trips to Jamaica , Martinique, and St. Lucia would indicate that the adults are capable of developing within a few days to two weeks (Nonsanchuk et al., 1995; Gardiner and Schantz, 1983).

CLINICAL PRESENTATION AND PATHOGENESIS: Cuadrado et al. (1980) report that histologically there is evidence of chronic inflammation of the nasopharynx. Humans with this infection have reported had non-productive and sometimes violent coughs (Freitas et al, 1995; Nosanchuk et al., 1995; Correa de Lara et al., 1993). No such clinical signs have been reported in cats.

TREATMENT: Treatment in humans has been performed with mebendazole (Correa de Lara et al., 1993; Timmons et al., 1983).

EPIZOOTIOLOGY: Little is known about the epizootiology of this parasite; however, the confinement of the parasite to tropical areas would indicate that the cycle is not readily completed in temperature or colder climates.

HAZARDS TO OTHER ANIMALS: The life cycle is not known, and it is possible that the free larvae are capable of infecting other hosts such as ruminants that might ingest them.

HAZARD TO HUMANS: It is possible that once the infective-stage larvae have developed and hatched from the eggs that they are infective to humans upon ingestion. However, it does not appear that these larvae are capable of skin penetration based on trials by Buckley (1934).

CONTROL/PREVENTION: This will not be possible until the biology of this parasite has been adequately described.


Buckley JJC. 1934. On Syngamusierei sp. nov. from domestic cats with some observations on its life-cycle. J Helminthol 12:89-98.

Cameron TWM. 1931. On some lungworms of the Malay tiger. J Helminthol 9:147-152.

Correa de Lara TA, Barbosa MA, Rodrigues de Oliveira M, Godoy, I, Queluz TT. 1993. Human syngamosis. Two case of chronic cough caused by Mammomonogamuslaryngeus. Chest 103:264-265.

Cuadrado R, Maldonado-Moll JF, Segarra J. 1980. Gapeworm infection of domestic cats in Puerto Rico. J Am Vet Med Assoc 176:996-997.

Euzeby J, Graber M, Gevrey J, Mejia A. 1977. Recent findings concerning Mammonmonogamus infection in America and the West Indies. Bull Acad Vet France 50:267-273.

Freitas AL, Carli G, Blankenhein MH?. 1995. Mammomogamus (Syngamus) laryngeus infection: a new Brazilian human case. Rev Inst Med Trop Sao Paulo 37:177-179.

Gardiner CH, Schantz PM. 1983. Mammomonogamus infection in a human. Report of a case. Am J Trop Med Hyg 32:995-997.

Macko JK, Birova V, Flores R. 1981. Deliberations on the problems of Mammomonogamus species (Nematoda, Syngamidae) in ruminants. Folia Parasitol 28:43-49.

Nosanchuk JS, Wade SE, Landolf M. 1995. Case report and description of parasite in Mammomonogamuslaryngeus (human syngamosis) infection. J Clin Microbiol 33:998-1000.

Ryzhikov KM. 1948. Phylogenetic relationship of nematodes of the family Syngamidae and an attempt to reconstruct their systematics. Dokl Acad Nauk SSSR 62:733-736.