Soft ticks Argasidae

Ticks are large blood-sucking Acari, sometimes > 1cm in length. There are three families of ticks, Argasidae, Ixodidae, and Nutalliellidae, consisting of a total of about 800 species. The latter family contains only one species of no known medical significance. The development of ticks is from an egg via one (Ixodidae) or more (Argasidae) nymphal stages to the adult stage. The larva has six legs while the nymph and adult have eight legs. The soft ticks Figure 23.7 The soft tick Ornithodoros....

Pediculus humanus the human clothing louse body louse

The body louse is morphologically very similar to the head louse and the two species were until recently treated as two subspecies, P. humanus humanus (synonym P. humanus corporis) and P. humanus capitis. However, the biology and medical importance of the two species are distinctly different. The primary microhabitat for all stages of the body louse is the clothes of humans. The blood-feeding stages (i.e. all stages except the eggs) only leave the clothes of its host in order to blood-feed on...

Prevalence of human parasites in Iceland

Richter, and Matthias Eydal The origin of human parasites in Iceland is discussed and historical information reviewed. Furthermore, the past and present status of endemic and imported human endo- and ectoparasites, recorded in Iceland so far, is reviewed. Several zoonotic parasites which have not been confirmed in humans and non-host specific species, which are capable of causing irritations on human skin, are also mentioned. Most endemic parasites are shortly...

Trichomonas vaginalis

Trichomonas vaginalis is a common sexually transmitted pathogen causing vaginitis, exocervicitis, and ureteritis in women (Fauts and Kraus 1980). Trichomonas vaginalis infections has been suggested to play a role in the pathogenesis of pre-term birth, pre-term rupture of membranes and delivery of low-birth-weight infants (Cotch et al. 1991 Read and Klebanoff 1993). Recently T. vaginalis infections has been implicated as a cofactor in the transmission of HIV (Laga et al. 1993). Trichomonas...

Research on human parasites in Iceland

Since 1881, annual reports on public health, written by local medical doctors, have been compiled and published by the Directorate General of Health in Iceland. These reports not only contain valuable information on the occurrence of sarcoptidosis and echinococcosis, the only notable human parasitic diseases in the country, but also on some other endemic parasites. During 1939-1962, a checklist of most parasitic groups occurring in Iceland was compiled by several foreign scientists and...

Dermanyssus gallinae the chicken mite red poultry mite

The chicken mite, Dermanyssus gallinae, has a world-wide distribution and is a nocturnally blood-feeding ectoparasite on domestic and wild birds. During the summer when synanthropic birds, for example, house sparrows, starlings or doves, have their nests inside or on the outside of human habitations, the mites will feed on the nestlings and their avian parents. When the birds leave the house the mites will try to find substitute hosts, which often happen to be people inhabiting the house. The...

Taxonomy

Giardia is the first protozoan parasite of man discovered as early as 1681 by Antony van Leeuwenhoek and described later by Lambl in 1859. It is a member of order Diplomonadida belonging to class Zoomastigophorea. The taxonomic name of the organism has been subjected, during the past years, to many changes. As many as seven different binomial labels of the parasite can be traced in the past. Giardia intestinalis and G. lamblia used currently are synonymous names for the human parasite, which,...

Arthropod resistance to synthetic and natural insecticides and acaricides

Resistance is defined by WHO (1992) as 'an inherited characteristic that imparts an increased tolerance to a pesticide, or group of pesticides, such that resistant individuals survive a concentration of the compound(s) that would normally be lethal to the species'. In practice, the operational criterion is usually taken as 20 or more survivors of individual arthropods tested to the normally used diagnostic concentration of the pesticide, using WHO test kits in the field. The appearance of...

Epidemiology and transmission

Pneumocystis carinii is ubiquitous and apparently encountered by the population in many geographical areas without disease manifestation (Pifer et al. 1978 Smulian et al. 1993). Most humans appear to be exposed to Pneumocystis within 2 years after birth (Hong 1991). An increased rate of seropositivity is seen with age (Meuwissen and Leeuwenberg 1972 Meuwissen et al. 1973) in children in Europe, the US, and Gambia. Despite the global presence of the organism, geographical differences are seen in...

References

Arthropods and human skin. Springer-Verlag, Berlin, Germany, 422 pp. Burgdorfer, W. (1975). A review of Rocky Mountain spotted fever (tick-borne typhus), its agent and its tick vectors in the United States. J. Med. Entomol. 12 269-278. Curtis, C. F. (1984). Low cost sanitation systems and the control of flies and mosquitoes. Trans. R. Soc. Trop. Med. Hyg. 78 298. Curtis, C. F. (ed.) (1991). Control of disease vectors in the community. Wolfe Publ. Ltd., London, 233...

Endoparasitic mites

Pictures Scabies Infection Knees

The scabies mite, Sarcoptes scabiei, is the cause of scabies in humans and other mammals. If man is infested by any of the forms of the scabies mite which normally parasitize animals the infestation usually disappears after some time. This is because each one of the different scabies mite populations are relatively host specific. The scabies mite is whitish to nearly transparent, almost round, and due to its size (1 3mm) hardly visible to the naked eye (Figure 23.5). The female scabies mite...

Pathogenesis of PCP

Today the term 'plasma cell pneumonia' is replaced by Pneumocystis pneumonia PCP , which reflects not only the recognition of the etiological agent, but also the histopathologically different appearance of the lung tissue in AIDS-associated PCP and the severe interstitial reaction seen in infected small children. Infection with P. carinii typically results in a pneumonia which is histologically seen to consist of an eosinophilic foamy alveolar exudate associated with a mild plasma cell...