Lagochilascaris minor

Lagochilascaris minor

<p align="CENTER"><span style="font-size: medium;"><i><b>Lagochilascaris minor</b></i></span><span style="font-size: medium;"><b> Leiper, 1909</b></span></p> <p align="CENTER"><span style="font-size: medium;"><b>(Figures 4-39 through 4-43)</b></span></p> <p align="JUSTIFY"><span style="font-size: medium;"><b>ETYMOLOGY:</b></span><span style="font-size: medium;"><i>Lago</i></span><span style="font-size: medium;"> (Hare) + </span><span style="font-size: medium;"><i>Chil</i></span><span style="font-size: medium;"> (Lip) + </span><span style="font-size: medium;"><i>Ascaris</i></span><span style="font-size: medium;">; along with </span><span style="font-size: medium;"><i>major</i></span><span style="font-size: medium;"> (due to being larger than the previously described </span><span style="font-size: medium;"><i>Lagochilascaris</i></span><span style="font-size: medium;"><i>minor</i></span><span style="font-size: medium;">).</span></p> <p align="JUSTIFY"><span style="font-size: medium;"><b>HISTORY:</b></span><span style="font-size: medium;"> In 1909, Leiper described a new genus and species of ascaridoid nematode based on worms collected from subcutaneous lesions from the necks of two human patients in Trinidad. Sprent (1971) reviewed the genus and reviewed the 11 cases that had been reported from humans in Trinidad, Surinam, Tobago, Costa Rica, and Brazil. In these cases worms had been recovered from subcutaneous tissues of the neck, the mastoid porocess, from tonsils, and passed from the nose. In 1991, it was reported that there had been a total of 62 cases from around the world, and that 46 of these cases were from Brazil (Costa and Weingrill, 1991). Since that time additional cases have been reported from Surinam (Oostburg,, 1992); Brazil (Aguilar-Nascimento, 1993; Bento et al., 1993); Bolivia (Olle Goig et al., 1996); and Mexico (Vargas-Ocampo and Alvarado-Aleman, 1997). </span><span style="font-size: medium;"><i>Lagochilascaris</i></span><span style="font-size: medium;"><i>minor</i></span><span style="font-size: medium;"> infection has been associated with fatal encephalopathy (Rosemberg et al., 1986; Orihuela et al., 1987). Volcán et al. (1992) performed experimental infections that incriminated the cat as a potential final host of this nematode.</span></p> <p align="JUSTIFY"><span style="font-size: medium;"><b>GEOGRAPHIC LOCATION:</b></span><span style="font-size: medium;"> All reports of natural infections have been in humans. Sprent (1971) summarized 11 cases from Tinidad, Tobago, Surinam, Costa Rica, and Brazil). More recent cases have included: Brazil (Bento et al., 1993); Bolivia (Olle-Goig et al., 1996); Mexico (Vargas-Ocampo et al., 1997); Surinam (Osostburg, 1992); Colombia (Botero and Little, 1984); and Venezuela (Orihuela et al., 1987). Two female worms recovered from the larynx of a bush dog (</span><span style="font-size: medium;"><i>Speothos</i></span><span style="font-size: medium;"><i>venaticus</i></span><span style="font-size: medium;">) in Venezuela appeared to be </span><span style="font-size: medium;"><i>Lagochilascaris</i></span><span style="font-size: medium;"><i>minor</i></span><span style="font-size: medium;"> (Volcán and Medrano, </span><span style="font-size: medium;">1993).</span><span style="font-size: medium;"> A species of </span><span style="font-size: medium;"><i>Lagochilascaris</i></span><span style="font-size: medium;"> was also found in the larynx of an ocelot (</span><span style="font-size: medium;"><i>Felis</i></span><span style="font-size: medium;"><i>pardalis</i></span><span style="font-size: medium;"><i>mearnsi</i></span><span style="font-size: medium;">) in Costa Rica (Brenes-Madrigal et al., 1972). </span></p> <p align="JUSTIFY"><span style="font-size: medium;"><b>LOCATION IN HOST:</b></span><span style="font-size: medium;"> In humans, the worms have been recovered from subcutaneous abscesses in the neck, the inner ear, the mastoid process, the tonsil, and in the parenchyma of the brain. In the cats that have been experimentally infected worms have been recovered from the lungs, cervical region, larynx, pharynx, rhinopharynx, and in sacs at the base of the tongue. Eggs are passed in the feces of these experimentally infected cats. In the North American opossum, </span><span style="font-size: medium;"><i>Didelphis</i></span><span style="font-size: medium;"><i>virginiana</i></span><span style="font-size: medium;">, the related species </span><span style="font-size: medium;"><i>Lagochilascscaris</i></span><span style="font-size: medium;"><i>sprenti</i></span><span style="font-size: medium;">, is foun in excavations under the mucosa of the stomach (Fig. 4-38)</span></p> <p align="JUSTIFY"><span style="font-size: medium;"><b>PARASITE IDENTIFICATION:</b></span><span style="font-size: medium;"> Adults of </span><span style="font-size: medium;"><i>Lagochilascaris</i></span><span style="font-size: medium;"> tend to be rather small worms with the total length of the males being around 17 to 20 mm and the length of the females being around 18 to 21 mm. The worms are cream colored. The vulva of the female is located at or slightly behind midbody. The lips are a distinguishing feature in that the dorsal lip and each of the subventral lips have a deep central cleft in the anterior border that gives them the typical “hare-lip” appearance. The anterior end of the worm is constricted between the base of the lips and the body of the worm, and there is an inflation of cuticle on the anterior of the worm behind this indentation that has been termed a collar. Extending anteriad from the collar are prolongations called interlabia that protrude foward between each of the three lips. The eggs of </span><span style="font-size: medium;"><i>Lagochilascaris</i></span><span style="font-size: medium;"> are the feature that can most easily be used to distinguish </span><span style="font-size: medium;"><i>Lagochilascaris major</i></span><span style="font-size: medium;"> from </span><span style="font-size: medium;"><i>Lagochilascaris</i></span><span style="font-size: medium;"><i>minor</i></span><span style="font-size: medium;">. Although the eggs are similar in size (around 60 μm in diameter) and general appearance having a thickened brown shell, the eggs of </span><span style="font-size: medium;"><i>Lagochilascaris</i></span><span style="font-size: medium;"><i>minor</i></span><span style="font-size: medium;"> have approximately 15 to 25 pits around the circumference while those of </span><span style="font-size: medium;"><i>Lagochilascaris</i></span><span style="font-size: medium;"><i>major</i></span><span style="font-size: medium;"> have approximately 33 to 45 pits around the circumference. It appears that the collar is more apparent on the anterior end of </span><span style="font-size: medium;"><i>Lagochilascaris</i></span><span style="font-size: medium;"><i>minor</i></span><span style="font-size: medium;"> and that the lips of </span><span style="font-size: medium;"><i>Lagochilascaris</i></span><span style="font-size: medium;"><i>minor</i></span><span style="font-size: medium;"> tend to be the same width or narrower than the collar while those of </span><span style="font-size: medium;"><i>Lagochilascaris</i></span><span style="font-size: medium;"><i>major</i></span><span style="font-size: medium;"> appear wider than the collar.</span></p> <p align="JUSTIFY"><span style="font-size: medium;"><b>LIFE CYCLE</b></span><span style="font-size: medium;">: Volcán et al. (1992) and Campos et al. (1992) showed that the cat could be infected by being fed mice that had been infected for 40 days; both sets of workers also reported that cats were not infected when simply fed eggs containing infective-stage larvae (Fig 4-49). In the work of Volcán et al. (1992) eggs first appeared in the feces beginning 17 days after infection, and 9 of the 10 cats fed mice were positive by 40 days after infection. Campos et al. (1992) found that 9 to 20 days after the feeding of mice that adult worms were present within the esophagus, pharynx, trachea, and cervical lymph nodes. Also, in one cat that had been infected for 43 days that the lesion in the lungs and cervical region contained adults, eggs containing developing larvae, and hatched third-stage larvae in various stages of development; and they postulated that the auto-infective cycle that is characteristic of human lesions may occur in the cat (figs 4-40 to 4-43).</span></p> <p align="JUSTIFY"><span style="font-size: medium;">Freire-Filha and Campos (1992) found that some of the larvae given to mice in infective eggs were capable of developing to adults within cysts in the muscles. Similar growth of larvae to adults in cysts in the muscle of mice was reported for the related species </span><span style="font-size: medium;"><i>Lagochilascaris</i></span><span style="font-size: medium;"><i>sprenti</i></span><span style="font-size: medium;"> when eggs of this parasite of the opossum (</span><span style="font-size: medium;"><i>Didelphis</i></span><span style="font-size: medium;"><i>virginiana</i></span><span style="font-size: medium;">) were fed to mice. The morphology of the larva of </span><span style="font-size: medium;"><i>Lagochilascaris</i></span><span style="font-size: medium;"><i>sprenti</i></span><span style="font-size: medium;"> that is typically found in the muscle of mice was described by Bowman (1987). The fact that </span><span style="font-size: medium;"><i>Lagochilascaris</i></span><span style="font-size: medium;"><i>sprenti</i></span><span style="font-size: medium;"> is typically found in the stomach wall of the opossum may indicate that the final host of </span><span style="font-size: medium;"><i>Lagochilascaris</i></span><span style="font-size: medium;"><i>minor</i></span><span style="font-size: medium;"> has actually yet to be found. </span></p> <p align="JUSTIFY"><span style="font-size: medium;"><b>CLINICAL PRESENTATION AND PATHOGENESIS</b></span><span style="font-size: medium;">: Cats show some signs of infection beginning nine days after being fed experimentally infected mice, i.e., slightly decreased motor activity, weak vocalizations, and frequent sneezing (Volcán et al., 1992). One of 10 experimentally infected cats developed a fistula in the posterior wall of the pharynx. A second cat developed destructive lesions at the based of the tongue with sacks that had inflamed walls and which contained mucus, eggs, and adult worms.</span></p> <p align="JUSTIFY"><span style="font-size: medium;"><b>TREATMENT:</b></span><span style="font-size: medium;"> Infections of humans with </span><span style="font-size: medium;"><i>Lagochilascaris minor</i></span><span style="font-size: medium;"> have proven refractory to treatment with anthelmintics. In humans the lesions may persist and living worms may be removed from the lesions for periods of several years. Treatment with high doses of diethylcarbamazine have apparently worked (de Leão et al., 1978), but have also been unsuccessful (Draper, 1963). Worms were recovered from this lesion for up to 10 years after the firfst diethylcarbamazine treatment (Sprent, 1971). Thiabendazole has worked in some cases (Oostburg, 1971), but has failed in other cases (Oostburg and Verma, 1968; Mondragon et al., 1973). Levamisole has apparently also worked on occasion (Santos et al., 1990) and failed on other occasions (Aguilar-Nascimento et al., 1993). Ivermectin has apparently has successfully treated one human case of infection (Bento et al., 1993).</span></p> <p align="JUSTIFY"><span style="font-size: medium;"><b>EPIZOOTIOLOGY:</b></span><span style="font-size: medium;"> The cat is probably not the normal final host of either </span><span style="font-size: medium;"><i>Lagochilascaris</i></span><span style="font-size: medium;"><i>minor</i></span><span style="font-size: medium;"> or Lagochi</span><span style="font-size: medium;"><i>l</i></span><span style="font-size: medium;">ascaris </span><span style="font-size: medium;"><i>major</i></span><span style="font-size: medium;">. Interestingly, cats have not been reported as naturally infected with </span><span style="font-size: medium;"><i>Lagochilascaris</i></span><span style="font-size: medium;"><i>minor</i></span><span style="font-size: medium;">, infections in cats have been described as due to </span><span style="font-size: medium;"><i>Lagochilascaris</i></span><span style="font-size: medium;"><i>major</i></span><span style="font-size: medium;">. The difference in pits on the circumference of the egg is a fairly easily discernable taxonomic character, suggesting that most diagnoses have been correct. Cats are probably acquiring their infections with these nematodes by the ingestion of intermediate hosts.</span></p> <p align="JUSTIFY"><span style="font-size: medium;"><b>HAZARDS TO OTHER ANIMALS:</b></span><span style="font-size: medium;"> Mice and agouti rats (</span><span style="font-size: medium;"><i>Dasyprocta</i></span><span style="font-size: medium;"><i>leporina</i></span><span style="font-size: medium;">) have been experimentally infected by the feeding of the eggs of this </span><span style="font-size: medium;"><i>Lagochilascaris</i></span><span style="font-size: medium;"><i>minor</i></span><span style="font-size: medium;">. In some mice, the larvae go onto develop into adults in abscesses within the musculature (Freire-Filha and Campos, 1992); similar growth of adults of </span><span style="font-size: medium;"><i>Lagochilascaris</i></span><span style="font-size: medium;"><i>sprenti</i></span><span style="font-size: medium;"> in the muscles of mice has also been described (Smith et al., 1983). The eggs passed in the feces require a period of days to become infectious, and thus, pose no threat when passed in the feces.</span></p> <p align="JUSTIFY"><span style="font-size: medium;"><b>HAZARD TO HUMANS:</b></span><span style="font-size: medium;"> Humans are considered the host most at risk for infections with Lagochilascaris minor. At this time, it is unclear how humans are becoming infected. They may be obtaining their infections by the ingestion of some improperly cooked meat and are mimicking a final host in a manner similar to the cat when fed the larvae of an infected mouse. On the other hand, humans developing lesions may be serving as some form of intermediate host, and like the mouse where worms develop to the adult stage in abscesses after the ingestion of eggs, the human may have acquired their infections by the ingestion of eggs containing infective-stage larvae.</span></p> <p align="JUSTIFY"><span style="font-size: medium;"><b>CONTROL/PREVENTION: </b></span><span style="font-size: medium;">This infection will be prevented preventing cats from hunting.</span></p> <p align="JUSTIFY"><span style="font-size: medium;"><b>REFERENCES:</b></span></p> <p align="JUSTIFY"><span style="font-size: medium;">Aguilar Nascimento JE, Silva GM, Tadano T, Valadares Filho M, Akiyama AMP, Castelo A 1993.Infection of the soft tissue of the neck due to </span><span style="font-size: medium;"><i>Lagochilascaris minor</i></span><span style="font-size: medium;"> Trans Roy Soc Trop Med Hyg 87:198.</span></p> <p align="JUSTIFY"><span style="font-size: medium;">Bento R F. Mazza C, Motti EF, Chan YT Guimaraes JRR, Miniti A. 1993. Human lagochilascariasis treated successfully with ivermectin: a case report. Revista do Instituto de Medicina Tropical de Sao Paulo 35:373-375.</span></p> <p align="JUSTIFY"><span style="font-size: medium;">Bowman D.D. 1987 Diagnostic morphology of four larval ascaridoid nematodes that may cause visceral larva migrans: </span><span style="font-size: medium;"><i>Toxascaris leonina</i></span><span style="font-size: medium;">, </span><span style="font-size: medium;"><i>Baylisascaris procyonis, Lagochilascaris sprenti</i></span><span style="font-size: medium;">, and </span><span style="font-size: medium;"><i>Hexametra leidyi</i></span><span style="font-size: medium;">. J Parasitol 73:1198-1215..</span></p> <p align="JUSTIFY"><span style="font-size: medium;">Costa VR, Weingrill EC. 1991. Lagoquilascaríase. Report of the 12 Congress of the Brazilian Society of Parasitology, Encarte 13:5.</span></p> <p align="JUSTIFY"><span style="font-size: medium;">Campos DMB, Freire-Filha LG, Vieira MA, Paçôm JM, Moacir AM. 1992. Experimental life cycle of </span><span style="font-size: medium;"><i>Lagochilascaris minor</i></span><span style="font-size: medium;"> Leiper, 1909. Rev Inst Med Trop São Paulo 34:277-287.</span></p> <p align="JUSTIFY"><span style="font-size: medium;">Campos DMB, Freire-Filha LG. 1992. Consideraçoes sobre o desenvolvimento de </span><span style="font-size: medium;"><i>Lagochilascaris minor</i></span><span style="font-size: medium;"> Leiper, 1909 em camundongos isogênicos da linhagem C57B1/6. Rev Pat Trop 21:219-233.</span></p> <p align="JUSTIFY"><span style="font-size: medium;">Draper JW.1963 Infection with</span><span style="font-size: medium;"><i> Lagochilascaris minor.</i></span><span style="font-size: medium;"> Br Med J 1:931-932.</span></p> <p align="JUSTIFY"><span style="font-size: medium;">de Leão RN, Leao-Filho J, Brago-Dias L, Calheiros LB 1978. Human infection with </span><span style="font-size: medium;"><i>Lagochilascaris minor</i></span><span style="font-size: medium;"> Leiper, 1909. A case history from Para State. Rev Instit Med Tropde Sao Paulo 20:300-306..</span></p> <p align="JUSTIFY"><span style="font-size: medium;">Leiper RT. 1909. A new nematode worm from Trinidad:</span><span style="font-size: medium;"><i> Lagochilascaris minor</i></span><span style="font-size: medium;"> sp. n. Proc Zool Soc Lon 4:35-36</span></p> <p align="JUSTIFY"><span style="font-size: medium;">Mondragon H, Cano MR, Botero DR. 1973. Primer caso de infecciíon humana por </span><span style="font-size: medium;"><i>Lagoichiascaris minor</i></span><span style="font-size: medium;"> en Colombia. Antioquia medica 23:463-464.</span></p> <p align="JUSTIFY"><span style="font-size: medium;">Ollé-Goig JE. 1996. First case of </span><span style="font-size: medium;"><i>Lagochilascaris minor</i></span><span style="font-size: medium;"> infection in Bolivia. Trop Med Int Heal 1:851-853. </span></p> <p align="JUSTIFY"><span style="font-size: medium;">Oostburg BFJ. 1992. Thiabendazole therapy of Lagochilascaris minor infection in Surnam, a report case. Am J Trop Med Hyg 20:580-583.</span></p> <p align="JUSTIFY"><span style="font-size: medium;">Oostburg BFJ, Verma AAO. 1968. Lagochilascaris minor infection in Surnam, a report case. Am J Trop Med Hyg 17:548-550.</span></p> <p align="JUSTIFY"><span style="font-size: medium;">Orihuela R, Botto C, Delgado O, Ortiz A, Suarez JA, Arguello C. 1987. Human Lagochilascarisis infection in Venezuela. Description of a fatal case. Inst Med Trop, Venezuela 20:217-221.</span></p> <p align="JUSTIFY"><span style="font-size: medium;">Vargas-Ocampo F, .Alvarado-Aleman J. 1997. Infestation from </span><span style="font-size: medium;"><i>Lagochilascaris minor </i></span><span style="font-size: medium;">in Mexico. Int J Dermatol 36:37-58.</span></p> <p align="JUSTIFY"><span style="font-size: medium;">Rosemberg S, Lopes MBS, Masuda Z, Campos R, Vieira Bressan MCR. 1986. Fatal encephalopathy due to </span><span style="font-size: medium;"><i>Lagochilascaris minor </i></span><span style="font-size: medium;">infection. Am J Trop Med Hyg 35:575-578.</span></p> <p align="JUSTIFY"><span style="font-size: medium;">Santos VM. 1990. Relato de caso de infecçao humana por </span><span style="font-size: medium;"><i>Lagochilascaris minor</i></span><span style="font-size: medium;">. An Bras Dermatol 65:189-192.</span></p> <p align="JUSTIFY"><span style="font-size: medium;">Smith JL, Bowman DD, Little MD. 1983. Life cycle and development of </span><span style="font-size: medium;"><i>Lagochilascaris sprenti</i></span><span style="font-size: medium;"> (Nematoda: Ascarididae) from opossums (Marsupialia: Didelphidae) in Louisiana. J Parasitol 69:736-745.</span></p> <p align="JUSTIFY"><span style="font-size: medium;">Sprent JFA. 1971. Speciation and development in the genus :</span><span style="font-size: medium;"><i>Lagochilascaris</i></span><span style="font-size: medium;">. Parasitol 62:71-112.</span></p> <p align="JUSTIFY"><span style="font-size: medium;">Volcán GS, Medrano CE, Payares G. 1992. Experimental heteroxenous cycle of </span><span style="font-size: medium;"><i>Lagochilascaris minor</i></span><span style="font-size: medium;"> Leiper, 1909 (Nematoda:Ascarididae) in white mice and incats. Mem Inst Oswald Cruz, Rio de Janeiro 87:525-532.</span></p> <p align="JUSTIFY"><span style="font-size: medium;">Volcán GS, Medrano CE, Quiñones D. 1991. Infeccion natural de </span><span style="font-size: medium;"><i>Speothos venaticus</i></span><span style="font-size: medium;"> (Carnivora: Canidae) por estadios adultos de </span><span style="font-size: medium;"><i>Lagochilascaris sp.</i></span><span style="font-size: medium;"> Rev Inst Med Trop São Paulo 33:451-458.</span></p> <p align="JUSTIFY"><span style="font-size: medium;"><b>FIGURES:</b></span></p> <p align="JUSTIFY"><span style="font-size: medium;"><b>Figure 4-38</b></span><span style="font-size: medium;">. </span><span style="font-size: medium;"><i>Lagochilascaris</i></span><span style="font-size: medium;"><i>sprenti</i></span><span style="font-size: medium;">. Section through the wall of the stomach of an opossum, </span><span style="font-size: medium;"><i>Didelphis</i></span><span style="font-size: medium;"><i>virginiana</i></span><span style="font-size: medium;">, showing the adult worms living in the typical submucosal excavation.</span></p> <p align="JUSTIFY"><span style="font-size: medium;"><b>Figure 4-39</b></span><span style="font-size: medium;">. </span><span style="font-size: medium;"><i>Lagochilascaris</i></span><span style="font-size: medium;"><i>sprenti</i></span><span style="font-size: medium;">. Infective third-stage larva expressed from an embryonated egg. Note the pedunculated knob at the end of the tail.</span></p> <p align="JUSTIFY"><span style="font-size: medium;"><b>Figure 4-40.</b></span><span style="font-size: medium;"><i>Lagochilascaris</i></span><span style="font-size: medium;"><i>sprenti</i></span><span style="font-size: medium;">. Section through the muscle tissue of an experimentally infected mouse showing the larva within an eosinophilic granuloma.</span></p> <p align="JUSTIFY"><span style="font-size: medium;"><b>Figure 4-41.</b></span><span style="font-size: medium;"><i>Lagochilascaris</i></span><span style="font-size: medium;"><i>sprenti</i></span><span style="font-size: medium;">. Large cyst that developed on the cheek of a mouse experimentally infected with this worm.</span></p> <p align="JUSTIFY"><span style="font-size: medium;"><b>Figure 4-42.</b></span><span style="font-size: medium;"><i>Lagochilascaris</i></span><span style="font-size: medium;"><i>sprenti</i></span><span style="font-size: medium;">. When the lesion from the cheek was opened, it was found to contain an adult nematode.</span></p> <p align="JUSTIFY"><span style="font-size: medium;"><b>Figure 4-43.</b></span><span style="font-size: medium;"><i>Lagochilascaris</i></span><span style="font-size: medium;"><i>sprenti</i></span><span style="font-size: medium;">. Section through another large cyst in an experimentally infected mouse showning the presence of both a large cyst containing an adult female and two sectons through smaller cysts containing larvae.</span></p>