Transovarial transmission
Encyclopedia
Transovarian transmission occurs in certain arthropod
vectors as they transmit disease-causing bacteria from parent arthropod to offspring arthropod. For instance, Rickettsia rickettsii
, carried within tick
s, is passed on from parent to offspring tick by transovarial transmission. In contrast, Rickettsia prowazekii
is not passed on by transovarian transmission because it kills the vector that carries it (human louse). This is the mechanism by which many Rickettsiae are maintained in their arthropod hosts through generations.which occurs also in aedes mosquito vector of the yellow fever virus and in phlebotomine sandflies
that transmit pappataci fever
.
Richard Dawkins in "The Extended Phenotype" page 222 (1999 edition) notes that "bacterial endosymbionts of insects which are transmitted transovarially" share an interest in the "success of their host's gametes.....as well as the survival of their host's body." In this case, "the interest of the host genes and parasite genes might not be quite identical, but they would..... be very much closer than the case of fluke and snail." where host and parasite have different means of propagation into the next generation, and therefore more divergent interests.
Contrast with transstadial transmission.
Arthropod
An arthropod is an invertebrate animal having an exoskeleton , a segmented body, and jointed appendages. Arthropods are members of the phylum Arthropoda , and include the insects, arachnids, crustaceans, and others...
vectors as they transmit disease-causing bacteria from parent arthropod to offspring arthropod. For instance, Rickettsia rickettsii
Rickettsia rickettsii
Rickettsia rickettsii is a unicellular, gram-negative coccobacillus that is native to the New World. It belongs to the spotted fever group of Rickettsia and is most commonly known as the causative agent of Rocky Mountain spotted fever . By nature, R...
, carried within tick
Tick
Ticks are small arachnids in the order Ixodida, along with mites, constitute the subclass Acarina. Ticks are ectoparasites , living by hematophagy on the blood of mammals, birds, and sometimes reptiles and amphibians...
s, is passed on from parent to offspring tick by transovarial transmission. In contrast, Rickettsia prowazekii
Rickettsia prowazekii
Rickettsia prowazekii is a species of gram negative, Alpha Proteobacteria, obligate intracellular parasitic, aerobic bacteria that is the etiologic agent of epidemic typhus, transmitted in the feces of lice. In North America, the main reservoir for R. prowazekii is the flying squirrel. R...
is not passed on by transovarian transmission because it kills the vector that carries it (human louse). This is the mechanism by which many Rickettsiae are maintained in their arthropod hosts through generations.which occurs also in aedes mosquito vector of the yellow fever virus and in phlebotomine sandflies
Phlebotominae
Members of the subfamily Phlebotominae are known outside of the United States by the name sand fly. This subfamily includes numerous genera of blood-feeding flies, including the primary vectors of leishmaniasis, bartonellosis and pappataci fever...
that transmit pappataci fever
Pappataci fever
Pappataci fever is a vector-borne febrile arboviral infection caused by three serotypes of Phlebovirus. Occurs in subtropical regions of the Eastern Hemisphere...
.
Richard Dawkins in "The Extended Phenotype" page 222 (1999 edition) notes that "bacterial endosymbionts of insects which are transmitted transovarially" share an interest in the "success of their host's gametes.....as well as the survival of their host's body." In this case, "the interest of the host genes and parasite genes might not be quite identical, but they would..... be very much closer than the case of fluke and snail." where host and parasite have different means of propagation into the next generation, and therefore more divergent interests.
Contrast with transstadial transmission.