Monkeypox Virus - Credit CDC PHIL
#16,954On Friday, the CDC published another report on environmental contamination inside a residence where (in this case, 2) Monkeypox-positive patients were living.
As we've seen previously (see EID Journal: Environmental Persistence of Monkeypox Virus on Surfaces in A Household and Eurosurveillance: Surface Contamination in Hospital Rooms Occupied by Patients Infected with Monkeypox), PCR testing revealed numerous contaminated surfaces.
Viral DNA can often be detected long after the virus is no longer viable, or in concentrations too low to be infectious, so a positive PCR swab result is followed up with a virus culture.
Unlike the two previous examples, in this study researchers were unable to culture a viable virus from any of the samples, which they suggest may be due to the cleaning routine used by the occupants of the house.
First, as link and excerpts from the MMWR report, after which I'll have a brief comment followed by a link to the CDC's recommendations on cleaning and disinfection of homes and non-healthcare facilities when Monkeypox contamination is suspected.
High-Contact Object and Surface Contamination in a Household of Persons with Monkeypox Virus Infection — Utah, June 2022
Early Release / August 19, 2022 / 71
Jack A. Pfeiffer1,2; Abigail Collingwood2; Linda E. Rider2; Faisal S. Minhaj1,3; Audrey M. Matheny3; Chantal Kling3; Andrea M. McCollum3; Leisha D. Nolen2; Clint N. Morgan3
PDF [257K]
In May 2022, the Salt Lake County Health Department reported two real-time polymerase chain reaction (PCR)–confirmed travel-associated cases of monkeypox to the Utah Department of Health and Human Services (UDHHS). The two persons with monkeypox (patients A and B) lived together without other housemates. Both persons experienced prodromal symptoms (e.g., fatigue and body aches). Eight days after symptom onset, patient A experienced penile lesions; lesions spread to the lips, hands, legs, chest, and scalp by day 10. Patient B experienced prodromal symptoms 8 days after illness onset of patient A; patient B experienced a lesion on the foot which spread to the leg and finger by day 11.
Although both patients had lesions in multiple anatomic areas, the overall number of lesions was small, and lesions varied in presentation from “pimple-like” or ulcerated, to characteristically well-circumscribed and centrally umbilicated. Both patients had mild illness. The time from symptom onset to resolution was approximately 30 days for patient A and approximately 22 days for patient B.
To assess the presence and degree of surface contamination of household objects contacted by monkeypox patients, UDHHS swabbed objects in the home of the patients. The patients identified high-contact objects and surfaces for sampling; the patients also described cleaning and disinfection activities performed within the home during their illness and locations within the home where they spent substantial amounts of time while ill. The patients had isolated at home for 20 days before their home was entered for sampling. The patients were still symptomatic at the time UDHHS collected specimens from their home. The temperature in the two-story home ranged from 69°F (20.6°C) to 75°F (23.9°C) during their period of isolation. CDC monkeypox-specific cleaning and decontamination guidance (1) was shared with the occupants at the time the home surfaces were swabbed.
UDHHS personnel entered the residence discreetly wearing recommended personal protective equipment (2). They performed targeted environmental sampling using published methods (3). Specimens were obtained from 30 objects in nine areas of the home and were transported to the Utah Public Health Laboratory for shipment to CDC where they were processed and tested with both nonvariola Orthopoxvirus and West African Monkeypox virus–specific real-time PCR assays (4,5). Viral culture was only pursued if the qualitative PCR result was positive.* This activity was reviewed by CDC and was conducted consistent with applicable federal law and CDC policy.†
Among the 30 specimens, 21 (70%) yielded positive real-time PCR results, including those from all three porous items (i.e., cloth furniture and blankets), 17 of 25 (68%) nonporous surfaces (e.g., handles and switches), and one of two mixed surface types (i.e., chair) (Table). No specimen yielded a positive viral culture result.
During the period of isolation both residents of the home reported showering once or twice each day, performing hand hygiene approximately 10 times daily, laundering bedding and clothing weekly, and performing routine household cleaning (e.g., mopping and daily use of a multisurface spray on most high-contact surfaces). The cleaning spray used was not listed on the Environmental Protection Agency’s List of Disinfectants for Emerging Viral Pathogens.§
Monkeypox virus DNA was detected from many objects and surfaces sampled indicating that some level of contamination occurred in the household environment. However, the inability to detect viable virus suggests that virus viability might have decayed over time or through chemical or environmental inactivation. Although both patients were symptomatic and isolated in their home for >3 weeks, their cleaning and disinfection practices during this period might have limited the level of contamination within the household. These data are limited, and additional studies are needed to assess the presence and degree of surface contamination and investigate the potential for indirect transmission of Monkeypox virus in household environments.
Monkeypox virus primarily spreads through close, personal, often skin-to-skin contact with the rash, scabs, lesions, body fluids, or respiratory secretions of a person with monkeypox; transmission via contaminated objects or surfaces (i.e., fomites) is also possible.¶ Persons living in or visiting the home of someone with monkeypox should follow appropriate precautions against indirect exposure and transmission by wearing a well-fitting mask, avoiding touching possibly contaminated surfaces, maintaining appropriate hand hygiene, avoiding sharing eating utensils, clothing, bedding, or towels, and following home disinfection recommendations.**,††
Acknowledgments
Ryan Chatelain, Salt Lake County Health Department; Kimberly Christensen, Utah Public Health Laboratory; CDC 2022 Multi-National Monkeypox Response.
As we've seen previously, porous materials (cloth, bedding, towels, etc.) appear to provide a much more hospitable home for the virus than either plastic or steel (non-porous) surfaces.
The inability of researchers to culture viable virus when both patients were still symptomatic and isolating in their home, is notable, and suggests that rigorous cleaning and disinfection can help reduce the risk of transmission.
The CDC's recommendations for disinfecting surfaces and laundry follow:
Disinfecting Home and Other Non-Healthcare Settings
Updated July 18, 2022
This document provides considerations on cleaning and disinfecting settings such as homes and cars that may be contaminated with Monkeypox virus. This information applies to the West African clade of Monkeypox virus only.
On This Page
Cleaning and Disinfection
Purpose of Home Disinfection
People with monkeypox who do not require hospitalization may be isolated at home. Monkeypox spreads between people through direct contact with an infectious rash, body fluids, or by respiratory secretions during prolonged, face-to-face contact. Transmission of Monkeypox virus is possible from the onset of the first symptoms until the scabs have separated and the skin has fully healed.
During the infectious period of time, body fluids, respiratory secretions, and lesion material from people with monkeypox can contaminate the environment. Poxviruses can survive in linens, clothing and on environmental surfaces, particularly when in dark, cool, and low humidity environments. In one study, investigators found live virus 15 days after a patient’s home was left unoccupied. Studies show that other closely related Orthopoxviruses can survive in an environment, similar to a household, for weeks or months. Porous materials (bedding, clothing, etc.) may harbor live virus for longer periods of time than non-porous (plastic, glass, metal) surfaces.
Orthopoxviruses are very sensitive to UV light. Despite the ability of Orthopoxviruses to persist in the environment, they are also sensitive to many disinfectants, and disinfection is recommended for all areas (such as home and vehicle) where a person with monkeypox has spent time, as well as, for items considered to be potentially contaminated.
