Helminths and the transmammary route of infection

Abstract

SUMMARYThe transfer of infective larval stages of helminths via the mammary glands is probably more common than generally recognized. Recent investigations of both natural and experimental infections of various animals have shown that the transmammary transmission of some helminths is a major avenue of infection. Other studies indicate that there are at least 13 helminth parasites which may be transmitted as prenatal infections and at least 17 transmitted via the mammary glands. The majority of these are nematodes. However, in one case the tetrathyridia of the cestode Mesocestoides was observed. In this report the life-cycle and transmission of 2 species of diplostomatid trematodes in the genus Pharyngostomoides is described. The raccoon, Procyon lotor, is the only definitive host; a planorbid snail, Menetus dilatatus, and a branchiobdellid annelid, Cambarincola osceola, a commensal on crayfishes, are intermediate hosts. Records for a period of 11 years are now available for the maternal transmission and longevity of this trematode. During this time one infected female raccoon was maintained in the laboratory on a diet of commercial dog food, sweet potatoes and corn. She produced 25 offspring, most of which were infected with Pharyngostomoides, through the 6th litter. There was a declining number of worms in each litter, ranging from nearly 2000 in one of the 1st litter, to none in the 7th litter. After nearly 12 years she continues to pass a few trematode ova. Rather than assume she has retained the same adult worms for 12 years, it is reasonable to conclude that mesocercariae move through her body and eventually mature in the intestine. Because the mesocercariae have a predilection for the lactating mammary gland, it seems likely that a hormonal influence is present. The transmammary transmission of larvae is a viable alternative in the life-cycles of a number of helminths, and in some instances it is probably the major route of infection.

Prenatal allergic sensitization to helminth antigens in offspring of parasite-infected mothers.

“…Thus, fetal allergic sensitization could occur by transplacental passage of soluble parasite antigens or intact microfilariae (frequently observed in filarial infections of animals and humans (23), or by actual prenatal infection with migrating third-stage larvae of W. bancrofti or antigenically related nematodes. Transplacental nematode infections occur commonly in animals (24) and have been reported sporadically in man (25). Whether or not true infection occurs, prenatal exposure to parasite antigen may influence subsequent immune responses of the host to filarial infection and thereby contribute to the extreme variability in disease expression observed in filariasis (26).…”

HELMİNT ENFEKStYONLARlı"lOA KONAKÇI CtNStYETİNİ!" ÖNEMİ

“…Galaktojen bulaşma Mesocestoides corti'de de bilinmektedir (7,21,31). Bu parazitin tetrathyridium'ları ile enfekte dişi fareleri % 41' nin uterus lumeninde parazitlere rastlanması, fötuslarda ise hiç parazit gözlenmemesi prenatal enfeksiyonun olmadığını göstermiştir.…”

“…Pfeiffer ve Supperer (26) S. papillosus ile enfekte edilen ve doğum sonrası yavrularını emziren ineklerin buzağıla-rında parazitlere rastladıklarını kaydetmişlerdir. Kuzulardaki enfeksiyonların daha çok galaktojenik olduğu bildirilmiştir (21,31 (34).…”

Prevention of Lactogenic Toxocara cati Infections in Kittens by Application of an Emodepside/Praziquantel Spot-on (Profender®) to the Pregnant Queen

“…transmission of developmental stages from the infected mother to the offspring either prenatally or by the transmammary pathway, is a major component in the life cycles of several species of parasitic helminths (Miller 1981;Shoop 1991). It occurs predominantly in nematodes, but some trematode species such as Alaria spp.…”