T-cell tests point to undetected MERS in Nigerian abattoir workers – University of Minnesota Twin Cities

UNAMID, Albert González Farran / Flickr cc
Since first being reported in 2012, the Middle East respiratory syndrome coronavirus (MERS-CoV) has remained largely prevalent in the Arabian Peninsula, with 84.3% of the 2,494 cases—and 90.9% of its 858 deaths—in Saudi Arabia as of November 2019.
A study published in The Lancet Infectious Diseases yesterday, however, proposes that human infections are underestimated in Africa because of ineffective testing. This finding highlights an anomaly: More than 70% of the primary MERS-CoV carriers, dromedary camels, reside on the continent, yet human cases are rarely reported there.
In an observational cohort study at an abattoir (slaughterhouse) in Kano, Nigeria, researchers found that 30% of their study population who were in close contact with dromedaries had peripheral blood mononuclear cell (PBMC) test results that showed MERS-CoV-specific CD4+ and CD8+ T-cell responses. These same participants had negative results on their serologic tests, the method most used to detect MERS-CoV in humans.
A T cell is a type of lymphocyte (white blood cell found in the lymphatic system) that plays a central role in the body’s immune response to a pathogen such as MERS-CoV. Serologic tests measure the amount of antibodies or proteins present in the blood. So both PBMC and serologic tests can indicate a previous infection, but previous studies have shown PBMC might be more sensitive.
Both tests were conducted from Mar 13 through 26, 2018, on 61 workers who were in close contact with dromedaries, 20 who worked at the abattoir but not with camels, 10 non-abattoir workers in the city, and—from May 10-Aug 31, 2018—on 24 additional control participants from Guangzhou, China.
The researchers found that 18 (30%) of the 61 abattoir workers with exposure to camels tested positive via PBMC, but none of the others did.
They also noted that 48 (79%) of the abattoir dromedary workers also drank camel milk or urine, which had a significant negative association with T-cell positivity. The investigators said this finding was surprising, but because of the small sample size they could not tease out the reasons for it. Some believe camel milk and urine to have medicinal properties.
In a Lancet commentary, Stanley Perlman, MD, PhD, of the University of Iowa, and Alimuddin Zumla, MBChB, PhD, of University College London, not only advocate for better surveillance and MERS-CoV control in Africa, but they consider how it could relate to the current pandemic.
“It would also be interesting to know if dromedary-exposed workers with MERS-CoV-specific T-cell responses are protected from developing severe MERS on rechallenge, and by extrapolation, whether T-cell responses are protective against severe COVID-19 disease, even if virus-specific antibody is not detectable,” they write. “The results also suggest that COVID-19 and MERS vaccines should be formulated to induce T-cell responses to maximize the likelihood of long-term protection.”
The experts, who were not involved in the study, also note, “Zoonotic [animal-origin] MERS-CoV infections of dromedary-exposed individuals are probably taking place in Nigeria, and, by extrapolation, the incidence of human MERS infections in all regions of Africa with dromedaries has probably been underestimated.”
Studies in South Africa and Vietnam also indicate 6 months of treatment with an oral antibiotic could help prevent development of MDR-TB in children and adults.
Hospitalizations are also up, especially in seniors and young children.
The extra dose reduced risk of infection by 41%, hospitalization or death by 65%.
The buck, which carried a GPS tracker, died in the middle of October.
The absolute difference in age-adjusted death rates between men and women increased from 252 to 315 per 100,000 from 2010 to 2021.
Most of the patients are babies who likely got sick after touching dog food or were exposed to dogs and their environments.
Exemptions increased in 41 states, and exceeded 5% in 10 states.
The researchers found no evidence of neuroinflammation.
New polling data reveals finds some concerns about virus spread over the holidays, but divided view on taking precautions.
The WHO lowered its treatment-benefit threshold from a 6% to a 2% reduction in the risk of hospitalization.
Help make CIDRAP’s vital work possible
CIDRAP – Center for Infectious Disease Research & Policy
Office of the Vice President for Research, University of Minnesota, Minneapolis, MN
Email us
© 2023 Regents of the University of Minnesota. All rights Reserved.
The University of Minnesota is an equal opportunity educator and employer
Office of the Vice President for Research |   Contact U of M  |  Privacy Policy
Newsletter subscribe


Leave a Reply

Your email address will not be published. Required fields are marked *