Resler et al. (2009) studied the movements of spermatozoa in the reproductive tract of female Ornithodoros moubata soft ticks, which become more pronounced after a blood meal.
Ornithodoros species are soft ticks (Family Argasidae). Included in this genus is Ornithodoros moubata, an important vector of tick-borne relapsing fever (TBRF) in humans in parts of Africa. Ornithodoros moubata transmits the spirochaete bacterium Borrelia duttonii, which causes TBRF. (Louse-borne relapsing fever [LBRF], the occurrence of which has been greatly reduced in recent decades, is caused by B. recurrentis, which genetic studies suggest may be a louse-adapted form of B. duttonii.) TBRF remains a major cause of child mortality in some African counries. TBRF may also be caused by B. crocidurae (transmitted by the soft tick O. sonrai) in West Africa and B. hispanica (transmitted by the soft tick O. erraticus) in North Africa, with B. duttonii dominating in East Africa, but this is not clearly established. (Cutler et al. 2009)
Like other argasids, Ornithodoros ticks have multihost life cycles. Argasid ticks have two or more nymphal stages, each requiring a blood meal from a host. Unlike the ixodid (hard) ticks, which stay attached to their hosts for up to several days while feeding, most argasid ticks are adapted to feeding rapidly (for about an hour), then dropping off the host.
Ornithodoros moubata, commonly known as the African hut tampan[1] or the eyeless tampan,[2] is a species of tick in the family Argasidae. It is an ectoparasite and vector of relapsing fever in humans,[3][4] and African swine fever in pigs.[2]
Soft ticks in the family Argasidae are characterised by the mouth being on the underside, and thus not visible from above, and by having no rigid scutum, the sclerotised plate on the anterior dorsal surface, just posterior to the head, possessed by hard ticks. This species has a leathery, wrinkled dorsal surface covered with small nodules. It has no eyes, and lacks a "suture line" at the junction of the dorsal and ventral surfaces. It has long mouthparts, armed with large, backward-pointing barbs for piercing a host's skin. The female grows to about 10 mm (0.4 in) long and the male to 8 mm (0.3 in).[5]
This species occurs in Kenya, Malawi, Mozambique, Namibia, South Africa, Tanzania, Uganda, Zambia, and Zimbabwe, but mainly in wildlife reserves. They also occur in southern Sudan, Somalia and southern Ethiopia, as well as the Democratic Republic of Congo, the Central African Republic and Chad, and infrequently in West Africa.[6]
The lifecycle of O. moubata involves several nymphal stages and one adult stage. Each of these stages requires a blood meal, suitable hosts being humans, poultry, and members of the pig family, Suidae.[6] When the nymph or adult has engorged itself, it drops off its host and enters a quiescent state while the blood is digested. When ready to feed again, it finds another host for this purpose. Adult females lay a batch of eggs, which hatch into larvae that develop into the first nymphal stage.[7]
Relapsing fever in humans is a vector-borne disease caused by infection with certain bacteria in the genus Borrelia.[8] It is transmitted through the bites of lice or soft-bodied ticks (genus Ornithodoros).[9] Human body lice are less common than in the past, because of better living conditions and the use of insecticides, and ticks may now be the main vectors for these bacteria. Each species of Borrelia is typically associated with a single tick species, with Borrelia duttoni being transmitted by O. moubata, and being responsible for the relapsing fever found in central, eastern, and southern Africa. Unlike in most other species of Borrelia, which have rodents as reservoir hosts, B. duttoni has humans as reservoir hosts.[10]
African swine fever is a vector-borne disease of domestic pigs, warthogs, and bushpigs, caused by infection with the African swine fever virus and carried by O. moubata. In wild members of the family Suidae, the disease seems symptomless, but in domestic pigs, it causes a haemorrhagic fever with high mortality rates. Transmission can be by tick bite or by eating infected tissues.[11]
Other infections that can survive inside this tick include West Nile virus, HIV, hepatitis B, Royal Farm virus, Langat virus, Rickettsia, Babesia equi, and Acanthocheilonema viteae, but only some of these can be transmitted by the ticks to humans. Although HIV-1BRU can remain viable in the tick's digestive tract for up to ten days, this is a shorter interval than the tick normally takes between blood meals, and laboratory tests indicate that mechanical transmission of HIV is unlikely.[1]
Ornithodoros moubata, commonly known as the African hut tampan or the eyeless tampan, is a species of tick in the family Argasidae. It is an ectoparasite and vector of relapsing fever in humans, and African swine fever in pigs.
