Blood mites are external parasites, known scientifically as ectoparasites, that sustain themselves by feeding on the blood of vertebrate hosts. These tiny organisms are classified as arachnids, placing them in the same class as spiders and ticks. They are minute, typically less than one millimeter in length, and their life cycle revolves around finding a host to secure a blood meal. This feeding behavior can lead to health concerns for the animals they target, as well as for humans who may be bitten when the mites’ preferred hosts are unavailable.
Identification and Common Hosts
Identifying blood mites often depends on recognizing two common species encountered in domestic settings: the poultry red mite and the tropical rat mite. The poultry red mite, Dermanyssus gallinae, is a major pest of domestic fowl and other birds. These mites appear grayish-white when unfed, but their bodies swell and turn a distinct reddish-brown after they have consumed blood. They measure approximately 0.75 to 1 millimeter long as adults.
The tropical rat mite, Ornithonyssus bacoti, primarily targets wild rodents like rats and mice, but they can infest other small mammals and occasionally bite humans. This species is slightly larger, ranging from 0.75 to 1.44 millimeters in length, and is typically grey before feeding, turning dark red once engorged. Both species are temporary parasites, spending the majority of their time off the host, hiding in the host’s environment. They congregate in crevices, cracks, nesting materials, and bedding, emerging only to feed, often under the cover of darkness.
The Threat: Feeding Habits and Health Effects
Blood mites are obligate blood feeders, meaning they must consume blood to complete their life cycle. The process of feeding involves the mites using specialized mouthparts to pierce the host’s skin, which causes immediate irritation and pain. In a heavy infestation, a single host animal, such as a chicken, can be attacked by thousands of mites, leading to rapid and significant blood loss.
The direct effects of this feeding can be severe, particularly for young or immunocompromised hosts. Sustained blood loss can cause anemia, characterized by paleness, weakness, and lethargy. For poultry, a severe infestation can result in the loss of up to 5% of a bird’s total blood volume in a single night, potentially leading to rapid mortality in young chicks.
Beyond the direct consequence of blood loss, the bites cause localized irritation and allergic reactions, resulting in pruritus and dermatitis. The intense itching often causes the host to scratch or peck at the affected areas, leading to broken skin and subsequent hair or feather loss. This damage creates entry points for secondary bacterial infections. Blood mites are also implicated as potential vectors for pathogenic organisms, including bacteria like Salmonellosis and viruses.
Eradication and Prevention Strategies
Eradication of blood mites requires a two-pronged approach, focusing on both the host animal and the environment where the mites hide. For animals like poultry, systemic treatments containing fluralaner can be administered through drinking water, which kills the mites when they take a blood meal from the treated host. For small mammals, a veterinarian may prescribe topical or systemic antiparasitic medications, such as selamectin, to clear the mites from the animal.
Since these mites spend the majority of their time off the host, environmental control is equally important to eliminate an infestation. The habitat, such as a coop or cage, must be thoroughly cleaned, removing all bedding and nesting materials. Mites hide deep inside cracks, crevices, and joints of housing structures, so these areas require targeted treatment.
Residual miticides can be applied to the empty environment, often requiring reapplication after a period to address mites that hatch from eggs. Physical control methods, such as desiccant dusts like diatomaceous earth, can also be utilized to dehydrate and kill the mites in their hiding spots. Prevention strategies include strict biosecurity measures, such as quarantining new animals before introduction. Routine monitoring of host animals and their housing allows for the early detection and control of mite populations.