Mites
Jerome Goddard in Public Health Entomology, 2022
Larval stage mites in the family Trombiculidae, sometimes called chiggers (Figure 18.1a), harvest mites, or red bugs, are medically important pests around the world, primarily because they cause dermatitis and may transmit the agent of scrub typhus. Adult chiggers are oval shaped (approximately 1 mm long) with a bright red, velvety appearance, but it is only the larval stage that attacks vertebrate hosts. Chigger larvae are very tiny (0.2 mm long), round mites with numerous setae (Figure 18.2). The mites may be red, yellow, or orange in color and have a single dorsal plate (scutum) bearing two sensillae and four to six setae. Identification to the species level is extremely difficult and expert technical help is required (see Chapter 8).
Arthropod-Specific Personal Protection Techniques
Gail Miriam Moraru, Jerome Goddard in The Goddard Guide to Arthropods of Medical Importance, Seventh Edition, 2019
Chigger mites (sometimes called red bugs) occur in grass, weeds, or leaves and get onto passing vertebrate hosts; therefore, personal protection measures for chiggers are similar to those for ticks. Tucking pants legs into socks or boots and spraying clothing with DEET-based repellents provide fairly good protection (Figure 33.4). Treating clothing with permethrin is very effective against chiggers. One study showed a 74.2% increase in protection from chiggers compared to untreated clothing and use of repellents.12 In addition, after exposure to infested outdoor areas, hot soapy baths or showers will help remove any chiggers, attached or unattached.
Scrub typhus and antibiotic-resistant Orientia tsutsugamushi
Published in Expert Review of Anti-infective Therapy, 2021
Chin-Te Lu, Lih-Shinn Wang, Po-Ren Hsueh
Adults pass O. tsutsugamushi to their offspring through transovarial transmission. Larva mites are the only parasite stage, while all other active stages are free-living; humans play no role in the Orientia mite life cycle and are dead-end hosts [9]. The occurrence of scrub typhus is frequently related to temperature, and sometimes to rainfall, with high transmission peaks before and after the rainy season in many regions of Southeast and East Asia; a regular year-round transmission is common in some tropical and subtropical regions [10–14]. Chiggers are abundant in locales with high relative humidity (60–85%), moderate temperature (20–30°C), low incidence of sunlight, and a dense substrate-vegetative canopy [11,15,16].
Diagnosis & management of alpha-gal syndrome: lessons from 2,500 patients
Published in Expert Review of Clinical Immunology, 2020
In many settings, the critical point is for the astute clinician to consider AGS as a possible cause of the patient’s symptoms and Figure 1 is included as a diagnostic algorithm. However, it is important to realize that some patients with AGS may not present with these characteristics. Despite point i) above, a significant number of pediatric cases of AGS has been reported [15] and children represent approximately 12% of subjects in one published cohort [16]. Although published data suggest that the condition in children has similar features to those of adult patients, it is not unusual for children with AGS to report a specific association with limited number of foods, predominance of GI symptoms, and particular relevance of activity (e.g. sports practice). Moreover, a study of over 200 patients with AGS found that 16% reported subjective symptom onset in less than 2 hours after consuming mammalian meat [16]. History of a tick bite, larval tick bites (e.g. seed tick bites), or ‘chigger’ bites can be supportive of AGS as a diagnosis but the absence of such a history is not uncommon. Tick bites can be painless, and about half of the people who develop a tick-borne infection may not even remember being bitten by a tick. ‘Chiggers’ is a term often mentioned in the South that has become synonymous with ‘very itchy, small, red bites’ that can occur in isolation or in large numbers. We often inquire about ‘chigger’ bites with patients to gain a history of bug bites in general and less in direct questioning of their exposure to members of the Trombiculidae family of insects. Whether Trombiculidae bites can lead to the development of alpha-gal IgE is unclear but is a research question under our investigation.
Related Knowledge Centers
- Dermatitis
- Papule
- Seta
- Tick
- Tunga Penetrans
- Skin Condition
- Neotrombicula Autumnalis
- Cell
- Host
- HIVes