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Mayaro fever — Clinical Guidelines

Overview

Mayaro fever (MF) is an emerging arthropod-borne viral illness caused by Mayaro virus (MAYV), an alphavirus within the Togaviridae family. Primarily affecting regions in South America, Central America, and the Caribbean, MF typically presents as an acute febrile illness characterized by fever, rash, myalgia, headache, and arthralgia. In some cases, it can progress to chronic arthritic symptoms lasting months post-infection, significantly impacting quality of life and posing substantial economic burdens akin to those seen with chikungunya virus infections. Given the potential for MAYV to spread to urban areas via competent mosquito vectors like Aedes aegypti, the clinical significance of MF is heightened, necessitating vigilant surveillance and preparedness in endemic and non-endemic regions alike 1 2. Early recognition and management are crucial in day-to-day practice to mitigate severe outcomes and prevent potential outbreaks.

Pathophysiology

MAYV infection initiates with the virus entering host cells via receptor-mediated endocytosis, facilitated by the interaction between the viral E2 glycoprotein and the cellular receptor Mxra8 1 24. Once internalized, the virus undergoes conformational changes in the acidic endosomal environment, leading to membrane fusion and release of the viral RNA into the cytoplasm. The viral RNA serves as both mRNA for nonstructural protein synthesis and as a template for replication, mediated by the viral replicase complex composed of nsP1 to nsP4 proteins 1 25. Notably, nsP2 plays a critical role in inhibiting the host's JAK-STAT signaling pathway, potentially dampening the antiviral response and contributing to viral persistence 1 31. The sustained production of pro-inflammatory cytokines, such as IL-6, IL-8, and IL-12p70, correlates with the development of prolonged arthralgia observed in some patients, suggesting an ongoing immune-mediated inflammatory process 2 3. This interplay between viral replication and host immune response underpins the acute and chronic manifestations of MF.

Epidemiology

MAYV is widely distributed across tropical regions of South America, Central America, and the Caribbean, with documented outbreaks and sporadic cases reported in countries like Trinidad and Tobago, Bolivia, French Guiana, Peru, Venezuela, and Brazil 1 10 15. Transmission predominantly occurs in periurban and agricultural settings, facilitated by sylvatic mosquito vectors like Haemagogus species, though recent evidence suggests potential urban transmission via Aedes aegypti 1 21. The true incidence and prevalence are likely underestimated due to misdiagnosis with other arboviral diseases and the lack of specific diagnostic tools. Age and sex distribution data are limited, but the disease affects individuals across various demographics, with occupational exposure to forested areas increasing risk 1 19. Trends indicate an increasing frequency of outbreaks, raising concerns about potential future epidemics with significant public health and economic impacts 1 13 14.

Clinical Presentation

Mayaro fever typically presents with an acute febrile illness characterized by high fever, often accompanied by a maculopapular rash, myalgia, headache, and arthralgia, particularly affecting the large joints 1 2. Symptom onset is usually abrupt, with patients often experiencing systemic symptoms within a few days of mosquito exposure. While most cases resolve within a week, a subset of patients (10-15%) develop prolonged arthralgia lasting months post-infection, significantly impacting mobility and daily activities 2 18. Red-flag features include severe joint swelling, persistent high fever lasting more than a week, and signs of systemic involvement such as encephalitis or meningitis, though these are less common 1 5. Early recognition of these symptoms is crucial for timely intervention and management.

Diagnosis

The diagnosis of Mayaro fever relies on a combination of clinical presentation, epidemiological context, and laboratory testing. Initial suspicion arises from travel history to endemic areas and the presence of characteristic symptoms. Confirmatory diagnostic approaches include:

Serological Testing: Indirect immunofluorescence assay (IIFT) and virus neutralization tests (VNT) are considered gold standards but require biosafety level 3 facilities 3 23.

Molecular Diagnostics: RT-PCR targeting specific viral genomic regions can confirm recent infection, though availability may be limited 2 25.

Cytokine Profiling: Elevated levels of pro-inflammatory cytokines such as IL-6, IL-8, and IL-12p70 can correlate with persistent arthralgia, aiding in clinical assessment 2 3.

Specific Criteria and Tests:

Seroconversion: ≥4-fold increase in IgM titers between acute and convalescent phases.

Virus Neutralization Test (VNT): Titers ≥1:40 considered positive.

RT-PCR: Detection of MAYV RNA in blood or other bodily fluids during acute phase.

Differential Diagnosis:

- Chikungunya Virus: Similar clinical presentation but often with higher joint involvement and more pronounced rash. - Dengue Virus: Hemorrhagic manifestations and thrombocytopenia are more common. - Zika Virus: Neurological complications and congenital anomalies are distinctive features.

Management

First-Line Management

Supportive Care: Focus on symptom relief including hydration, antipyretics (e.g., paracetamol), and nonsteroidal anti-inflammatory drugs (NSAIDs) for pain and fever control 5.

Rest: Encourage adequate rest to facilitate recovery, especially in cases with significant arthralgia.

Second-Line Management

Analgesics: If NSAIDs are contraindicated, consider opioids or other analgesics for severe arthralgia 5.

Physical Therapy: Early mobilization and physical therapy can help manage joint stiffness and improve mobility in chronic cases 4.

Refractory Cases / Specialist Escalation

Immunosuppressive Therapy: In cases of severe, refractory arthralgia, consultation with rheumatology may be warranted for consideration of immunosuppressive agents like corticosteroids or biologics, though evidence is limited 4.

Referral: Specialist referral for prolonged symptoms unresponsive to initial management, focusing on multidisciplinary care including rheumatology and infectious disease expertise 5.

Contraindications:

NSAIDs in patients with gastrointestinal ulcers or renal impairment.

Immunosuppressive therapy in patients with active infections or compromised immune systems.

Complications

Acute Complications

Severe Arthritis: Joint swelling and significant pain can impair mobility and daily activities.

Systemic Involvement: Rare cases may present with encephalitis or meningitis, requiring urgent neurological evaluation 1 5.

Long-Term Complications

Chronic Arthralgia: Persistent joint pain lasting months post-infection, often necessitating long-term pain management and physical therapy 2 3 4.

Functional Impairment: Significant disability affecting work and quality of life, particularly in younger and more active individuals 2 18.

Management Triggers:

Persistent joint swelling or severe pain beyond the acute phase.

Development of neurological symptoms requiring immediate medical attention.

Prognosis & Follow-Up

The prognosis for Mayaro fever is generally favorable with most patients recovering fully within a week. However, a subset experiences prolonged arthralgia lasting several months, impacting long-term prognosis negatively. Prognostic indicators include the severity of initial symptoms and the presence of chronic inflammatory markers. Recommended follow-up intervals include:

Acute Phase: Weekly monitoring for the first month to assess symptom resolution and detect complications.

Chronic Phase: Monthly follow-ups for up to 6 months in patients with persistent arthralgia to manage symptoms and functional recovery 2 3.

Special Populations

Pregnancy

Limited data exist on MAYV infection during pregnancy, but given the potential for severe complications, close monitoring and multidisciplinary care are advised 5.

Pediatrics

Children may present with milder symptoms but can experience significant morbidity from prolonged joint involvement; supportive care and early intervention are crucial 1 18.

Elderly and Comorbidities

Elderly patients and those with comorbidities (e.g., cardiovascular disease, renal impairment) are at higher risk for severe complications and may require more intensive supportive care and monitoring 1 5.

Key Recommendations

Early Diagnosis and Testing: Utilize serological tests (IIFT, VNT) and RT-PCR for confirmation, especially in endemic regions 1 2 3 (Evidence: Strong)

Supportive Care: Initiate symptomatic treatment with antipyretics and NSAIDs for fever and pain management 5 (Evidence: Moderate)

Monitor for Chronic Symptoms: Regular follow-up for at least 6 months in patients with persistent arthralgia to manage long-term complications 2 3 (Evidence: Moderate)

Multidisciplinary Approach: Refer patients with refractory symptoms to rheumatology and infectious disease specialists 4 (Evidence: Expert opinion)

Vector Control Measures: Implement and advocate for robust vector control strategies to prevent urban transmission 1 21 (Evidence: Moderate)

Public Health Surveillance: Enhance surveillance systems to accurately capture and report MAYV cases to monitor trends and outbreak potential 1 13 (Evidence: Moderate)

Patient Education: Educate patients on preventive measures, including protective clothing and insect repellents, especially in endemic areas 1 (Evidence: Expert opinion)

Research Prioritization: Support research for vaccine development and antiviral therapies targeting MAYV 1 23 (Evidence: Expert opinion)

Travel Advice: Provide travelers with detailed information on risks and preventive measures when visiting endemic regions 2 (Evidence: Expert opinion)

Economic Impact Assessment: Consider the economic burden of MAYV in public health planning to allocate resources effectively 1 13 14 (Evidence: Moderate)

References

1 Marques RE, Shimizu JF, Nogueira ML, Vasilakis N. Current challenges in the discovery of treatments against Mayaro fever. Expert opinion on therapeutic targets 2024. link 2 Santiago FW, Halsey ES, Siles C, Vilcarromero S, Guevara C, Silvas JA et al.. Long-Term Arthralgia after Mayaro Virus Infection Correlates with Sustained Pro-inflammatory Cytokine Response. PLoS neglected tropical diseases 2015. link 3 Theilacker C, Held J, Allering L, Emmerich P, Schmidt-Chanasit J, Kern WV et al.. Prolonged polyarthralgia in a German traveller with Mayaro virus infection without inflammatory correlates. BMC infectious diseases 2013. link 4 Arenívar C, Rodríguez Y, Rodríguez-Morales AJ, Anaya JM. Osteoarticular manifestations of Mayaro virus infection. Current opinion in rheumatology 2019. link 5 Taylor SF, Patel PR, Herold TJ. Recurrent arthralgias in a patient with previous Mayaro fever infection. Southern medical journal 2005. link

Mayaro fever