Mucormycosis-induced brain abscess treatment without dura opening- a report of three cases (preprint)

purpose Brain abscess following sinonasal mucormycosis is a rare but life-threatening condition that usually occurs during the patient's treatment. Therefore, it is important to pay close attention to its identification and treatment and since our knowledge is mostly based on case reports, a well-documented way of treatment for such cases is yet to be found. Methods A retrospective case series study was conducted at a tertiary hospital. Initially, all patients with brain abscesses following sino-nasal mucormycosis were included, and then patients whose brain abscesses were treated without opening the dura during surgery were selected for the study. The patients received radical debridement of necrotic tissues as well as the infected bones adjacent to the brain abscess cavity. But the dura was not incised. Then they were treated medically for their underlying disease and also with Amphotericine-B. Their brain abscess was monitored 3 weeks post-operatively. Results Three patients with an average age of 41 years were included in the study. All patients had a history of diabetes and had previously been treated for COVID-19 before developing symptoms of sino-nasal infection. The average size of the abscesses was less than 2 cm. Two patients had abscesses in the temporal lobe and one in the frontal lobe. Conclusion Treating brain abscesses adjacent to the skull base by removing infected tissues and bones surrounding the brain abscess without opening the dura can be a viable treatment option for mucormycosis-induced brain abscesses of less than 2 cm. Ethics approval statement: IR.TUMS.AMIRALAM.REC.1402.036

Central Retinal Artery Occlusion in Rhino-Orbital-Cerebral Mucormycosis: An Inflammatory-Prothrombotic State.

PURPOSE: The aim was to evaluate patient profiles of rhino-orbital-cerebral mucormycosis (ROCM) cases with central retinal artery occlusion (CRAO) postcoronavirus disease 2019. DESIGN: A nonrandomized retrospective case-control study. METHODS: The ROCM cases presenting with CRAO were compared with a control ROCM group without CRAO at a tertiary care center. Demography, systemic status, clinical features, histopathology, imaging, and blood profile were assessed for any specific risk factors. RESULTS: A total of 12 patients were seen in the CRAO group and 16 in the non-CRAO group. The male-to-female ratio was 3:1 with a mean age of 49.5 years. In the CRAO group, 75% had diabetes mellitus with mean hemoglobin A1c of 9.03%, and 66.7% had received steroid treatment. All cases were histopathologically confirmed positive for mucor. There was a significant difference in mean D-dimer and serum ferritin between the 2 groups, with higher level in the CRAO group. All patients with CRAO had light perception-negative vision, with total ophthalmoplegia and proptosis seen in 66.7% of cases. Four patients had orbital apex involvement, 5 had cavernous sinus involvement, and 8 had intracranial involvement in the CRAO group. CONCLUSIONS: Inflammatory markers D-dimer and serum ferritin were significantly associated with CRAO, suggestive of hyperinflammatory and hypercoagulable state. A high index of suspicion should be maintained in cases with elevated markers and prophylactic anticoagulants can be started to prevent CRAO in a subset of patients.

Implementation of a telephone triage system for management of acute nasal fracture in response to the coronavirus disease 2019 pandemic (preprint)

Background Acute nasal fracture is a common referral to ENT outpatient clinic. During the Covid-19 pandemic, NHS outpatient services were increasingly stretched and placed patients and staff at risk of Coronavirus. Virtual clinic appointments provided an effective method for reducing Covid-19 risk and improving the efficiency of outpatient services. We sought to implement a telephone triage system for the assessment of nasal fractures.Method A telephone triage pathway for nasal fracture was implemented in October 2021. Data on nasal fracture appointments and outcomes were retrospectively collected for 2 months prior to, and after, the introduction of the telephone triage pathway. All patients with suspected nasal fracture referred to ENT by the Emergency Department at Colchester Hospital were included.Results At baseline, 32 patients were referred for face-to-face (F2F) clinic, 20 (62%) attended and 12 (38%) did-not-attend (DNA). Of those who attended, 17 (85%) were managed conservatively and 3 (15%) had manipulation under anaesthetic (MUA). 24 patients were included in the telephone triage pathway, 13 (54%) attended and 11 (46%) DNA. Of those who attended, 11 (84%) were discharged and 2 (16%) were brought in for F2F assessment. One was managed conservatively and the other had a MUA (8%). The increase in DNA rate from the F2F pathway to the telephone triage pathway was not statistically significant.Conclusion Our data suggests that the telephone triage system for nasal fracture management results in fewer F2F appointments. This reduces COVID-19 transmission to the public and hospital staff but also improves utilisation of outpatient capacity.

Uncontrolled diabetes mellitus exacerbated by COVID-19-induced inflammation is the risk factor for COVID-19-associated rhino-orbito-cerebral mucormycosis: A matched pair case-control study.

Purpose: Amidst the ongoing coronavirus disease 2019 (COVID-19) pandemic, India experienced an epidemic of COVID-19-associated rhino-orbito-cerebral mucormycosis (ROCM). This study aimed to describe the epidemiology and elucidate the risk factors for developing COVID-19-associated ROCM, comparing the risk factors among COVID-19 patients with and without ROCM. Methods: This case-control study included all COVID-19-associated ROCM patients treated at our hospital from May 1 to July 30, 2021. Controls included age- and sex-matched COVID-19 patients without ROCM, who were treated during the same time (exact matching, in 1:2 ratio). Matched pair analysis using conditional logistic regression was performed to examine the association of various risk factors with the development of ROCM in COVID-19 patients. Results: The study included 69 patients with COVID-19-associated ROCM and 138 age- and gender-matched controls. Epidemiologically, COVID-19-associated ROCM predominantly affected males (59/69, 85%), in their early 50s (mean 52 years), with 48% (33/69) of patients being from medical resource-constrained settings. On multivariate conditional logistic regression, elevated serum glycated hemoglobin (HbA1c) (odds ratio [OR] = 1.36, 95% confidence interval [CI]: 1.03-1.78), blood glucose (OR = 1.008, 95% CI: 1.003-1.013), and C-reactive protein (CRP) (OR = 1.07, 95% CI: 1.02-1.17) were associated with increased odds of developing COVID-19-associated ROCM. Patients with undetected diabetes mellitus with increasing HbA1c (OR = 3.42, 95% CI: 1.30-9.02) and blood glucose (OR = 1.02, 95% CI: 1.005-1.03) (P = 0.02) had a higher probability of developing COVID-19-associated ROCM than patients with established DM. Conclusion: Uncontrolled DM evidenced by elevated HbA1c and blood glucose levels, exacerbated by COVID-19-induced proinflammatory state indicated by elevated CRP, is the principal independent risk factor for COVID-19-associated ROCM. Middle-aged males with undetected DM, from a resource-constraint setting, are particularly at risk.

Clinical Features and Mortality of COVID-19-Associated Mucormycosis: A Systematic Review and Meta-Analysis.

The recent increase of COVID-19-associated mucormycosis (CAM) has been commanding global attention. However, basic epidemiologic characteristics have not firmly been established. In this systematic review and meta-analysis, we sought to determine the clinical manifestations, potential risk factors, and outcomes of CAM. Observational studies reporting CAM were searched with PubMed and EMBASE databases in January 2022. We collected data on comorbidities and treatment for COVID-19, and performed a one-group meta-analysis on the frequency of orbital exenteration procedure and mortality of CAM using a random-effect model. Fifty-one observational studies, including a total of 2,312 patients with proven CAM, were identified. Among the 51 studies, 37 were conducted in India, 8 in Egypt, and 6 in other countries. The most common comorbidity was diabetes mellitus (82%). While 57% required oxygenation, 77% received systemic corticosteroids. Among CAM, 97% were rhino-orbital-cerebral (ROCM), and 2.7% were pulmonary mucormycosis. Usual presentations were headache (54%), periorbital swelling/pain (53%), facial swelling/pain (43%), ophthalmoplegia (42%), proptosis (41%), and nasal discharge/congestion (36%). Regarding the outcomes, orbital exenteration was performed in 17% (95% CI: 12-21%, I2 = 83%) of the COVID-19-associated ROCM patients. The mortality of CAM was 29% (95% CI; 22-36%, I2 = 92%). In conclusion, this systematic review and meta-analysis indicated that the most prevalent type of CAM was ROCM, and most CAM patients had diabetes mellitus and received systemic glucocorticoids. Clinicians in the endemic areas should have a high index of suspicion for this invasive fungal complication of COVID-19 when a diabetic patient who received high-dose systemic glucocorticoids developed rhino-orbital symptoms.

Acupuncture for nasal congestion in COVID-19: A protocol for systematic review and meta-analysis.

BACKGROUND: From the end of 2019 to now, coronavirus disease 2019 (COVID-19) has put enormous strain on the world's health systems, causing significant deaths and economic losses worldwide. Nasal congestion, one of the symptoms of COVID-19, poses considerable problems for patients. In China, acupuncture has been widely used to treat nasal congestion caused by COVID-19, but there is still a lack of evidence-based medical evaluation. METHODS: According to the retrieval strategies, randomized controlled trials on the acupuncture for COVID-19 nasal congestion were obtained from China National Knowledge Infrastructure, WanFang, VIP, PubMed, Embase, and Cochrane Library, regardless of publication date, or language. Studies were screened based on inclusion and exclusion criteria, and the Cochrane risk bias assessment tool was used to evaluate the quality of the studies. The meta-analysis was performed using Review Manager (RevMan 5.3) and STATA 14.2 software. Ultimately, the evidentiary grade for the results will be evaluated. RESULTS: The study will provide a high-quality and convincing assessment of the efficacy and safety of acupuncture in the treatment of COVID-19's nasal congestion and will be published in peer-reviewed journals. CONCLUSION: Our findings will provide references for future clinical decision and guidance development. PROSPERO REGISTRATION NUMBER: NO.CRD42021299482.

Evaluation of the role of home rapid antigen testing to determine isolation period after infection with SARS-CoV-2 (preprint)

Importance Recent CDC COVID-19 isolation guidance for non-immunocompromised individuals with asymptomatic or mild infection allows ending isolation after 5 days if asymptomatic or afebrile with improving symptoms. The role of rapid antigen testing in further characterizing the risk of viral transmission to others is unclear. Objective Understand rates of rapid antigen test (RAT) positivity after day 5 from a positive COVID-19 test and the relationship of this result to symptoms and viral culture. Design In this single center, observational cohort study, ambulatory individuals newly testing SARS-CoV-2 positive completed daily symptom logs, and RAT self-testing starting day 6 until negative. Anterior nasal and oral swabs were collected on a subset for viral culture. Main Outcomes and Measures Day 6 SARS-CoV-2 RAT result, symptoms and viral culture. Results 40 individuals enrolled between January 5 and February 11, 2022 with a mean age of 32 years (range 22 to 57). 23 (58%) were women and 17 (42%) men. All were vaccinated. 33 (83%) were symptomatic. Ten (25%) tested RAT negative on day 6. 61 of 90 (68%) RATs performed on asymptomatic individuals after day 5 were positive. Day 6 viral cultures were positive in 6 (35%) of 17 individuals. A negative RAT or being asymptomatic on day 6 were 100% and 78% predictive respectively for negative culture, while improving symptoms was 69% predictive. A positive RAT was 50% predictive of positive culture. Conclusion and Relevance RATs are suboptimal in predicting viral culture results on day 6. Use of routine RATs to guide end of COVID-19 isolation could result in significant numbers of culture negative, potentially non-infectious individuals undergoing prolonged isolation. However, a negative RAT was highly predictive of being culture negative. Complete absence of symptoms was inferior to a negative RAT in predicting a negative culture result, but performed better than improving symptoms. If a positive viral culture is a proxy for infectiousness, these data may help further refine a safer strategy for ending isolation.

A model-based approach to improve intranasal sprays for respiratory viral infections (preprint)

Drug delivery for viral respiratory infections, such as SARS-CoV-2, can be enhanced significantly by targeting the nasopharynx, which is the dominant initial infection site in the upper airway, for example by nasal sprays. However, under the standard recommended spray usage protocol (“Current Use”, or CU), the nozzle enters the nose almost vertically, resulting in sub-optimal deposition of drug droplets at the nasopharynx. Using computational fluid dynamics simulations in two anatomic nasal geometries, along with experimental validation of the generic findings in a different third subject, we have identified a new “Improved Use” (or, IU) spray protocol. It entails pointing the spray bottle at a shallower angle (almost horizontally), aiming slightly toward the cheeks. We have simulated the performance of this protocol for conically injected spray droplet sizes of 1 – 24 μ m, at two breathing rates: 15 and 30 L/min. The lower flowrate corresponds to resting breathing and follows a viscous-laminar model; the higher rate, standing in for moderate breathing conditions, is turbulent and is tracked via Large Eddy Simulation. The results show that (a) droplets sized between ∼ 6 – 14 μ m are most efficient at direct landing over the nasopharyngeal viral infection hot-spot; and (b) targeted drug delivery via IU outperforms CU by approximately 2 orders-of-magnitude, under the two tested inhalation conditions. Also quite importantly, the improved delivery strategy, facilitated by the IU protocol, is found to be robust to small perturbations in spray direction, underlining the practical utility of this simple change in nasal spray administration protocol.

COVID-19-associated rhino-orbital-cerebral mucormycosis: A systematic review, meta-analysis, and meta-regression analysis.

BACKGROUND: Till now, no meta-analysis is available to address the clinical profile, risk factors, different interventions, and outcomes among COVID-19-associated rhino-orbito-cerebral mucormycosis (C-ROCM) cases. MATERIALS AND METHODS: Eight literature databases were screened using appropriate keywords from November 1, 2019, to June 30, 2021. The objectives were to analyze the clinical and microbiological profile, risk factor/comorbidity, intervention, and outcome. "R-metafor package" was used for analysis. RESULTS: A total of 23 studies were included. The mean age of presentation of C-ROCM was 54.6 years. The most common presentation was ptosis (72.7%), lid edema (60.6%), proptosis (60.6%), ophthalmoplegia (57.3%), loss of vision (53.7%), facial edema (34.7%), and nasal-blockage (11.8%). Evidence of intracranial spread was seen in 42.8% of cases. Rhizopus was the most common fungus (57.1%) isolated in fungal culture. Among C-ROCM patients, diabetes was the commonest comorbid condition, and the use of corticosteroids related to COVID-19 treatment was the most common risk factor (85.75%). Compared to controlled diabetics, C-ROCM was significantly higher among uncontrolled diabetics (odds ratio [OR] 0.15, 95% confidence interval [C.I.] 0.041-0.544, P = 0.0010). However, no significant association was seen between C-ROCM and COVID-19 severity (OR 0.930, 95% C.I. 0.212-4.087, P = 0.923). For treatment, amphotericin-B was the most common antifungal drug used which was followed by surgical options. However, mortality was high (prevalence 0.344, 95% C.I. 0.205-0.403) despite treatment. CONCLUSION: Although local rhino-orbito symptoms were the first to appear, rapid intracranial extension was seen in a significant number of C-ROCM cases. Uncontrolled diabetes and excessive use of corticosteroid were the most common risk factors present among the C-ROCM cases. High index clinical suspicion is imperative (specifically among COVID-19 patients with diabetes), and routine screening may be helpful.

Effects of the COVID-19 Pandemic on Pediatric Nasal Fractures.

OBJECTIVES: Nasal bone fracture is a frequent entity consulted to the otolaryngologists, approximately accounting for 39% of all facial bone fractures. The most frequent mechanisms of injury consist of assault, sport-related injuries, falls, and motor vehicle accidents. In this study, we examined the effects of the COVID-19 pandemic on pediatric nasal fractures. METHODS: Children with nasal fracture who applied to Malatya Training and Research Hospital during the year before the first case and the following year were included in this study. Data of 172 patients for the pre-pandemic period and 79 patients for pandemic were available and included in the study. Demographic information, clinical features, nasal fracture etiology, nasal fracture type, type and time of intervention, and other accompanying pathologies were recorded. RESULTS: While falls was the leading cause of fracture etiology before the pandemic (64 patients [37.21%]), assault seems to be the leading cause during the pandemic period (27 children [34.18%]). In the pre-pandemic period, the intervention for patients with nasal fractures was performed on an average of 5 days, while this period was calculated as an average of 6 days during the pandemic period. When the 2 groups are compared in terms of nasal fracture intervention time, it was seen that the intervention time was statistically significantly later in the pandemic period (P < .001). According to the results of the analysis, the most cases in the pandemic period were seen in the fourth month, which indicated a-month period between 11 June and 11 July. CONCLUSIONS: In conclusion, our number of nasal fracture cases was decreased during the pandemic period compared to the 1-year period before the pandemic. We observed the most common type IIA nasal fracture. We gave outpatient treatment to most of the patients. Our most common cause of fracture was assault. We intervened in our cases in an average of 6 days and preferred closed reduction most frequently. We could not find any study on the same subject in the literature, and we aimed to contribute to the literature with this study.

One year into the COVID-19 pandemic: What do we know so far from studies assessing risk and mitigation of droplet aerosolisation during endonasal surgery? A systematic review.

OBJECTIVES: As we pass the anniversary of the declaration of a global pandemic by the World Health Organisation, it invites us to reflect upon the inescapable changes that coronavirus has wrought upon ENT and, in particular, rhinological practice. As it remains unclear when we will emerge from the shadow of COVID-19, a critical analysis of the evidence base on both the assessment and mitigation of risk is vital for ENT departments worldwide. This article presents a systematic review of the literature examining articles which consider either the quantification of risk or strategies to mitigate risk specifically in the setting of rhinological surgery. DESIGN: Systematic literature review. RESULTS: The literature search yielded a total of 3406 returns with 24 articles meeting eligibility criteria. A narrative synthesis stratified results into two broad themes: (1) those which made an assessment as to the aerosolisation of droplets during sinus surgery, further sub-divided into work which considered macroscopically visible droplets and that which considered smaller particles; (2) and those studies which examined the mitigation of this risk. CONCLUSION: Studies considering the aerosolisation of both droplets and smaller particles suggest endonasal surgery carries significant risk. While results both highlight a range of innovative adjunctive strategies and support suction as an important intervention to reduce aerosolisation, appropriate use of personal protective equipment (PPE) should be considered mandatory for all healthcare professionals involved in rhinological surgery. Studies have demonstrated that close adherence to PPE use is effective in preventing COVID-19 infection.

Rhino-orbital-cerebral-mucormycosis in COVID-19: A systematic review.

Since the onset of COVID-19 pandemic, parallel opportunistic infections have also been emerging as another disease spectrum. Among all these opportunistic infection, mucormycosis has become a matter of concern with its rapid increase of cases with rapid spread as compared to pre-COVID-19 era. Cases have been reported in post-COVID-19-related immune suppression along with the presence of comorbidity which adds on the deadly outcome. There is no systematic review addressing the issue of COVID-19-associated mucormycosis. This is the first systematic review of published studies of mucormycosis associated with COVID-19. The aim was to analyze the real scenario of the disease statement including all the published studies from first November 2019 to 30th June to analyze the contemporary epidemiology, clinical manifestations, risk factor, prognosis, and treatment outcome of COVID-19 associated rhino-orbito-cerebral-mucormycosis. A comprehensive literature search was done in following databases, namely, PubMed, Google Scholar, Scopus, and EMBASE using keywords mucormycosis, rhino orbital cerebral mucormycosis, COVID-19, and SARS-CoV-2 (from November 01, 2019 to June 30, 2021). Our study shows that, while corticosteroids have proved to be lifesaving in severe to critical COVID-19 patients, its indiscriminate use has come with its price of rhino-orbito-cerebral mucormycosis epidemic, especially in India especially in patients with preexisting diabetes mellitus with higher mortality. Corticosteroid use should be monitored and all COVID-19 patients should be closely evaluated/monitored for sequelae of immunosuppression following treatment.

Magnetic resonance imaging in rhino-orbital-cerebral mucormycosis.

Coronavirus disease-associated mucormycosis (CAM) is an established clinical entity in India. In the past 4 months, there has been a sharp upsurge in the number of CAM cases in most parts of the country. Early diagnosis can be lifesaving. Magnetic resonance imaging (MRI) imaging remains the corner stone of management in patients with ROCM. This review discussed the utility of MRI imaging in ROCM with an emphasis on the ideal MRI protocol in a suspected case of ROCM, the pathways of spread of infection, the classic diagnostic features, MRI for staging of the disease, MRI for prognostication, MRI for follow up, and imaging features of common differentials in ROCM. The pit falls of MRI imaging and a comparison of CT and MRI imaging in ROCM are discussed. The clinical interpretation of areas of contrast uptake and those of necrosis and its relevance to treatment are discussed. This review aims to familiarize every member of the multidisciplinary team involved in managing these patients to be able to interpret the findings on MRI in ROCM.

Detection of persistent SARS-CoV-2 IgG antibodies in oral mucosal fluid and upper respiratory tract specimens following COVID-19 mRNA vaccination (preprint)

Previous studies have shown that mRNA COVID-19 vaccines are highly effective at preventing SAR-CoV-2 infection by generating an immune response, which in part produces SARS-CoV-2 IgG antibodies in serum. In this study, we hypothesized that COVID-19 vaccines may elicit production of SARS-CoV-2 IgG antibodies in the upper respiratory tract, such as in oral and nasal mucosal fluid. To test that hypothesis, we enrolled 114 participants within 3-7 days of receiving the first dose of the Moderna mRNA COVID-19 vaccine and collected oral mucosal fluid samples on days 5, 10, 15, and 20 after each vaccine dose. Of participants naive to SARS-CoV-2 (n = 89), 79 (85.4%) tested positive for SARS-CoV-2 IgG antibodies by time point 2 (10 days +/-2 days after first vaccine dose), and 100% tested positive for SARS-CoV-2 IgG by time point 3 (15 days +/-2 days after first vaccine dose). Additionally, we collected paired oral mucosal fluid and anterior nares samples from 10 participants who had received both vaccine doses. We found that participants had an average SARS-CoV-2 IgG antibody concentration of 2496.0 +/-2698.0ng/mL in nasal mucosal fluid versus 153.4 +/-141.0ng/mL in oral mucosal fluid. Here, we demonstrate detection and longitudinal persistence of SARS-CoV-2 IgG antibodies in upper respiratory tract specimens following COVID-19 mRNA vaccination.

Comfort rules for face masks among healthcare workers during COVID-19 spread.

BACKGROUND: The outbreak of Coronavirus disease 2019 (COVID-19) made imperative the use of protective devices as a source control tool. As there is no definite antiviral treatment and effective vaccine, the only efficient means of protecting and mitigating infectious contagion has been the use of personal protective equipment, especially by healthcare workers. However, masks affect the humidification process of inhaled air, possibly leading to a basal inflammatory state of the upper airways. STUDY DESIGN: This is a single-center observational study conducted at the University Hospital of Catania from April 1, 2020, to June 31, 2020. METHODS: We analyzed the role of protective masks on the elimination of upper airways complaints in healthcare workers of the University Hospital of Catania. We evaluated 277 subjects through a self-administered 17 item questionnaire based on respiratory, work performance and health-related quality of life domains. RESULTS: A higher prevalence of nasal and ocular symptoms, perceived reduced work performance, difficulty in concentrating, and sleep disorders were found. After two weeks adhering to a list of good practices that we recommended, significant reversibility of the symptoms investigated and work performance enhancement were observed. CONCLUSIONS: Despite clinical complaints related to personal protective equipment, effective amelioration through usage rules is easily obtained. Given the essential use of protective masks, healthcare workers have to adhere to appropriate work and safety prevention rules.

Type I and III IFNs produced by the nasal epithelia and dimmed inflammation are key features of alpacas resolving MERS-CoV infection (preprint)

While MERS-CoV (Middle East respiratory syndrome Coronavirus) provokes a lethal disease in humans, camelids, the main virus reservoir, are asymptomatic carriers, suggesting a crucial role for innate immune responses in controlling the infection. Experimentally infected camelids clear infectious virus within one week and mount an effective adaptive immune response. Here, transcription of immune response genes was monitored in the respiratory tract of MERS-CoV infected alpacas. Concomitant to the peak of infection, occurring at 2 days post inoculation (dpi), type I and III interferons (IFNs) were maximally transcribed only in the nasal mucosa of alpacas, provoking the induction of interferon stimulated genes (ISGs) along the whole respiratory tract. Simultaneous to mild focal infiltration of leukocytes in nasal mucosa and submucosa, upregulation of the anti-inflammatory cytokine IL10 and dampened transcription of pro-inflammatory genes under NF-κB control were observed. In the lung, early (1 dpi) transcription of chemokines (CCL2 and CCL3) correlated with a transient accumulation of mainly mononuclear leukocytes. A tight regulation of IFNs in lungs with expression of ISGs and controlled inflammatory responses, might contribute to virus clearance without causing tissue damage. Thus, the nasal mucosa, the main target of MERS-CoV in camelids, is central in driving an efficient innate immune response based on triggering ISGs as well as the dual anti-inflammatory effects of type III IFNs and IL10. Author summary Middle East respiratory syndrome coronavirus (MERS-CoV) is the etiological agent of a respiratory disease causing high mortality in humans. In camelids, the main MERS-CoV reservoir host, viral infection leads to subclinical disease. Our study describes transcriptional regulations of innate immunological pathways underlying asymptomatic clinical manifestations of alpacas in response to MERS-CoV. Concomitant to the peak of infection, these animals elicited a strong transient interferon response and induction of the anti-inflammatory cytokine IL10 in the nasal mucosa. This was associated to a dimmed regulation of pro-inflammatory cytokines and induction of interferon stimulated genes along the whole respiratory mucosa, leading to the rapid clearance of the virus. Thus, innate immune responses occurring in the nasal mucosa appear to be the key in controlling MERS-CoV disease by avoiding a cytokine storm. Understanding on how asymptomatic host reservoirs counteract MERS-CoV infection will aid in the development of antiviral drugs and vaccines.