Dermanyssus gallinae

Dermanyssus gallinae

<p align="CENTER"><i><b>Dermanyssus gallinae</b></i><b> (DeGeer, 1778) </b></p> <p align="CENTER"><b>(Figure 5-19)</b></p> &nbsp; <span style="font-size: medium;"><b>ETYMOLOGY:</b></span><span style="font-size: medium;"><i>Derma</i></span><span style="font-size: medium;"> = skin and </span><span style="font-size: medium;"><i>nyssus</i></span><span style="font-size: medium;"> = to prick; along with </span><span style="font-size: medium;"><i>gallinae</i></span><span style="font-size: medium;"> for the chicken host</span> &nbsp; <span style="font-size: medium;"><b>SYNONYMS:</b></span> &nbsp; <p align="JUSTIFY"><span style="font-size: medium;"><b>HISTORY:</b></span><span style="font-size: medium;"><i>Dermanyssus gallinae</i></span><span style="font-size: medium;">, which primarily affects avians, was first described by DeGeer in 1778. This mite infests cats only occasionally (Grant, 1985).</span></p> <p align="JUSTIFY"></p> <p align="JUSTIFY"><span style="font-size: medium;"><b>GEOGRAPHIC DISTRIBUTION:</b></span><span style="font-size: medium;"> The mite is worldwide in its distribution, attacking the fowl, pigeon, canary and other cage birds (Harwood and James, 1979). </span></p> <p align="JUSTIFY"></p> <p align="JUSTIFY"><span style="font-size: medium;"><b>LOCATION IN HOST:</b></span><span style="font-size: medium;"><i>Dermanyssus gallinae</i></span><span style="font-size: medium;"> is a nonburrowing, blood-sucking mite that usually infests birds or their domiciles (Regan </span><span style="font-size: medium;"><i>et al</i></span><span style="font-size: medium;">., 1987). This mite on rare occasions is found within the haircoat of cats (Grant, 1985). A case of this mite infesting the cat in the United States revealed lesions consisting of erosions, crusts, and excoriations on the head (Muller </span><span style="font-size: medium;"><i>et al</i></span><span style="font-size: medium;">., 1983). Grant (1989) reports lesions on the dorsum and the extremities of the cat.</span></p> <p align="JUSTIFY"></p> <p align="JUSTIFY"><span style="font-size: medium;"><b>IDENTIFICATION:</b></span><span style="font-size: medium;"><i>Dermanyssus gallinae</i></span><span style="font-size: medium;"> is often referred to as the red mite of poultry, but it is only red if it has recently fed on its host's blood. In the unfed state, this mite is white, grey or black. The fully engorged adult female is about 1 mm long or longer (Fig. 5-19). All other developmental stages are smaller. This mite possesses a very prominent dorsal shield. The shield does not quite extend to the posterior end of the body and its posterior end is truncated. The hairs on the dorsal shield are smaller than those on the carapace that surrounds the shield. On the posterior ventral surface of the mite is a prominent anal plate; the anus is located on the posterior aspect of this plate. This mite possessed long, whip-like chelicerae. Many of these key morphologic features can only be visualized after the mites have been cleared in lactophenol and examined under a compound microscope.</span></p> <p align="JUSTIFY"></p> <p align="JUSTIFY"><span style="font-size: medium;"><b>LIFE CYCLE:</b></span><span style="font-size: medium;"> The majority of this mite's life cycle takes place in the domicile of the avian definitive host. Following a blood meal, eggs are laid in the nests of birds or in the cracks and crevices in the wall of poultry houses. Up to seven eggs are laid at a time. At outdoor summer temperatures, the eggs hatch in two to three days, releasing the six-legged larvae, which do not feed. The larvae molt to the eight-legged protonymph stage, which will feed on the host's blood. After another one to two days, they develop into deutonymphs. These feed on blood and after another one to two days, then molt to adults. Under optimum conditions, the entire life cycle can be completed in seven days to five months (Grant, 1989). Under experimental conditions, the adult mites have been able to live for 34 weeks without a blood meal. </span></p> <p align="JUSTIFY"></p> <p align="JUSTIFY"><span style="font-size: medium;"><b>CLINICAL PRESENTATION AND PATHOGENESIS:</b></span><span style="font-size: medium;"> Mites often infest wild birds nesting in the eaves of homes. These mites may enter open windows and infest the people or their pets living there. Most cases associated with pets are found in cats or dogs that have access to or live in recently converted poultry houses. Clinical signs include erythema and papulocrustous eruptions which are intensely pruritic. These lesions are often distributed over the back and extremities (Muller </span><span style="font-size: medium;"><i>et al</i></span><span style="font-size: medium;">., 1983). </span></p> <p align="JUSTIFY"></p> <p align="JUSTIFY"><span style="font-size: medium;"><b>DIAGNOSIS:</b></span><span style="font-size: medium;"> Infestations with </span><span style="font-size: medium;"><i>Dermanyssus</i></span><span style="font-size: medium;"><i>gallinae</i></span><span style="font-size: medium;"> are often diagnosed by a history of contact with poultry houses or by close examination of environmental conditions (eg., eaves, air conditioners, open windows, etc.) associated with a building that birds use for nesting (Muller </span><span style="font-size: medium;"><i>et al.</i></span><span style="font-size: medium;">, 1983, Regan </span><span style="font-size: medium;"><i>et al</i></span><span style="font-size: medium;">., 1987). The mites are visible to the naked eye, particularly if they have fed recently on blood, and as a result, they are red in color. Diagnosis is by finding the mites on skin scraping (Muller </span><span style="font-size: medium;"><i>et al</i></span><span style="font-size: medium;">., 1983). When suspected mites are removed from an infested host, cleared in lactophenol and examined under a compound microscope, they will demonstrate the key morphologic features necessary for identification: size, number of legs, the very prominent dorsal shield with its truncated posterior end, and the ventral anal plate with the anus located on the posterior aspect.</span></p> <p align="JUSTIFY"></p> <p align="JUSTIFY"><span style="font-size: medium;"><b>TREATMENT:</b></span><span style="font-size: medium;"><i>Dermanyssus</i></span><span style="font-size: medium;"><i>gallinae</i></span><span style="font-size: medium;"> is susceptible to most insecticidal preparations; almost any bath, dip, or spray will eliminate the mites (Muller </span><span style="font-size: medium;"><i>et al.</i></span><span style="font-size: medium;">, 1983).</span></p> <p align="JUSTIFY"></p> <p align="JUSTIFY"><span style="font-size: medium;"><b>EPIZOOTIOLOGY:</b></span><span style="font-size: medium;"> Most cases of </span><span style="font-size: medium;"><i>Dermanyssus</i></span><span style="font-size: medium;"><i>gallinae</i></span><span style="font-size: medium;"> in the cat occur when there is an association of cats with poultry houses. The possibility of spread from pigeons or pigeon nests around houses also exists (Muller </span><span style="font-size: medium;"><i>et al</i></span><span style="font-size: medium;">., 1983).</span></p> <p align="JUSTIFY"></p> <p align="JUSTIFY"><span style="font-size: medium;"><b>HAZARDS TO OTHER ANIMALS:</b></span><span style="font-size: medium;"> Ramsay and Mason (1975) reported a case in a dog which was so infested that the numbers of mites crawling through the haircoat resembled the dandruff produced in infestations with </span><span style="font-size: medium;"><i>Cheyletiella</i></span><span style="font-size: medium;"> species.</span></p> <p align="JUSTIFY"></p> <p align="JUSTIFY"><span style="font-size: medium;"><b>HAZARDS TO HUMANS:</b></span><span style="font-size: medium;"> When pigeons nest near human dwellings, these mites may attack humans. </span><span style="font-size: medium;"><i>Dermanyssus</i></span><span style="font-size: medium;"><i>gallinae</i></span><span style="font-size: medium;"> is only one of six mites that may produce fowl mite dermatitis in humans. In the absence of an avian host, this mite will attack humans, producing a pruritic, macular, papular, vesicular, or urticarial rash. It may also serve as a potential vector for the viruses of eastern and western equine encephalomyelitis and Saint Louis encephalitis (Regan, 1987). Laboratory and epidemiologic studies suggest that these mites play no important role in the maintenance of these pathogens. Field isolation probably means that the mite has recently fed on viremic birds (Harwood and James, 1979). </span></p> <p align="JUSTIFY"></p> <p align="JUSTIFY"><span style="font-size: medium;"><b>CONTROL/PREVENTION:</b></span><span style="font-size: medium;"> Treatment of the infested premises that serve as the source of infestation should be accomplished to prevent reinfestation (Muller </span><span style="font-size: medium;"><i>et al</i></span><span style="font-size: medium;">., 1983).</span></p> <p align="JUSTIFY"></p> <p align="JUSTIFY"><span style="font-size: medium;"><b>LITERATURE CITATIONS</b></span></p> <p align="JUSTIFY"><span style="font-size: medium;">Grant DI. 1985. Notes on parasitic skin disease in the dog and cat. Br Vet J 141:447-462. </span></p> <p align="JUSTIFY"><span style="font-size: medium;">Grant DI. 1989. Parasitic diseases in cats. J Sm Anim Prac 30:250-254.</span></p> <p align="JUSTIFY"><span style="font-size: medium;">Harwood RF, James MT. 1979. </span><span style="font-size: medium;"><span style="text-decoration: underline;">Helminths, Arthropods, and Protozoa of Domesticated Animals. 7th edition</span></span><span style="font-size: medium;">. Macmillan. New York. P. 347. </span></p> <p align="JUSTIFY"><span style="font-size: medium;">Ramsay GW and Mason PC. 1975. Chicken mite (</span><span style="font-size: medium;"><i>D</i></span><span style="font-size: medium;">. </span><span style="font-size: medium;"><i>gallinae</i></span><span style="font-size: medium;">) infesting a dog. N Zealand Vet J 62:701.</span></p> <p align="JUSTIFY"><span style="font-size: medium;">Regan AM, Metersky ML, and Craven DE. 1987. Nosocomial dermatitis and pruritus caused by pigeon mite infestation. Arch Intern Med 147:2185-2187</span></p> <p align="JUSTIFY"><span style="font-size: medium;">Muller GH, Kirk, RW, and Scott, DW. 1983. </span><span style="font-size: medium;"><span style="text-decoration: underline;">Small Animal Dermatology</span></span><span style="font-size: medium;">. 3rd edition. W.B. Saunders. Philadelphia. P. 317. </span></p> <p align="JUSTIFY"></p> <p align="JUSTIFY"></p> <p align="JUSTIFY"><span style="font-size: medium;"><b>Figure 5-19. </b></span><span style="font-size: medium;"><i>Dermanyssus</i></span><span style="font-size: medium;"><i>gallinae</i></span><span style="font-size: medium;">. Adult mite, notice the long, narrow, chelicerae.</span></p>