Dermatitis and potential for zoonotic infections

The bite of O. bacoti can be painful and is typically followed by the eruption of a pruritic erythematous macular rash. The rash can be concentrated in body parts that are accessible by the mite or at parts around tightly fitting clothes.^{Reference Engel, Welzel, Maass, Schramm and Wolff1} Vesicular rash and nodules have also been described. Treatment is directed toward symptom management with antihistamines and glucocorticoids since the mite is easily washed with a shower without the requirement of mite directed therapies.

O. bacoti and L. sanguineus have the potential for the transmission of zoonotic infections. L. sanguineus is the main known carrier of Rickettsia akari. ^{Reference Paddock, Koss and Eremeeva2} A few reports in the literature regarding zoonotic infections directly linked to O. bacoti have described endemic typhus transmission and Bartonella henselae infection. Experimental studies have shown the potential for vector transmission of the agents of Q fever, tularemia, and epidemic hemorrhagic fever, coxsackievirus, Yersinia pestis, and rickettsialpox.^{Reference Watson5}

Rickettsialpox cases have been reported across the United States and it remains endemic in New York City. Some reports have revealed exoskeletons of L. sanguineus in buildings and others have described isolated cases without clear identification of a mite.^{Reference Koss, Carter and Grossman6}

Eradication

Complete eradication of mite infestations can be challenging and requires coordination to eliminate both the mites and the rodents. Following rodent extermination, mites can travel hundreds of feet and can survive for weeks without feeding. Thus, reinfestation is common but can be prevented by employing multiple treatments. The early identification of outbreaks could facilitate eradication, thus minimizing the impact on human health. In addition to juvenile hormone analog and abamectin, several other pesticides, including benzyl benzoate and gamma benzene hexachloride 1% (Lindane) or fumigated silica aerogel dust into walls, have been used to eradicate tropical rat mites.^{Reference Fishman7}

Rodent activity in urban centers

Climate change leading to warmer, wet winters and drought in the summers is conductive to the expansion of rodent populations. Furthermore, urbanization can affect the behavioral traits of rodents making them more explorative and bolder and increasing the likelihood of close contact with humans.^{Reference Dammhahn, Mazza, Schirmer, Göttsche and Eccard8} Boston reported its highest number of rodent complaints in 2021 compared to prior years, according to the city’s 311 data. The city of Chicago reported a 39% increase in public rat complaints from 2008 to 2017. Similar findings have been reported in California, Texas, and New York City.⁹ This growing rodent problem in urban centers will inevitably increase human exposure to vectorborne illnesses and zoonotic diseases.

In conclusion, successful and expeditious eradication of a clinic infestation by O. bacoti and L. sanguineus were achieved due to several important actions: (1) rapid identification of the mites utilizing the expertise of a veterinary parasitology consultant; (2) collaboration between the infection prevention team, clinic leadership, occupational health, environmental health and safety, environmental services, laboratory leadership, and hospital leadership; and (3) aggressive mitigation, which included necessary demolition of walls and other structures. Our experience could provide direction in future outbreaks.