Retrospective #Phylogenetic Analysis of #Mayaro Virus, French #Guiana, 1996–2024

 

Abstract

We conducted a retrospective phylogenetic analysis of Mayaro virus (MAYV) detected in French Guiana during 1996–2024. Analysis revealed circulation of MAYV genotype D sublineage 2 and suggested introduction from Brazil and spread to Haiti and Venezuela. Phylogenetic findings support endemic circulation and reinforce the need for MAYV surveillance in the region.

Source: 

Link: https://wwwnc.cdc.gov/eid/article/32/5/25-1435_article

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#Chikungunya fever: #Brazil is intensifying its response to address health emergency in Dourados (MoH, April 4 '26)

 

{Edited}

The Brazilian government has intensified its response to the emergency situation in Dourados (MS), given the increase in cases of chikungunya, with the mobilization of an interministerial task force that integrates actions in health, assistance, civil defense, and logistical support in the territory. The emergency affects the population of the municipality, with a greater impact on indigenous communities.

As a reinforcement to the response already underway, the Federal Government has guaranteed more than R$ 3.1 million in emergency resources for the municipality. 

Of this total, R$ 1.3 million , authorized by the Ministry of Integration and Regional Development (MIDR) in a decree published this Thursday (2), will be allocated to relief and humanitarian assistance actions, such as direct support to the population and local response structures. 

Also this Thursday, the National Secretariat for Civil Protection and Defense approved a work plan worth R$ 974,100 for restoration actions, including urban cleaning, waste removal and disposal in a licensed sanitary landfill, with resources to be transferred directly to the municipality.

The Ministry of Health has already transferred R$ 855,300 to the municipality to cover the costs of surveillance, assistance, and control actions related to chikungunya in the region.

The federal response has been underway since mid-March, coordinated by the Ministry of Health, which mobilized the National Health System (SUS) Task Force , reinforced healthcare teams, and intensified vector surveillance and control actions across the territory. 

The operation includes actively searching for cases, conducting home visits, eliminating [mosquitoes] breeding sites, and expanding services to the population, with special attention to the most vulnerable areas, including indigenous territories.

The National Health System Task Force has 40 mobilized professionals , with 26 currently working directly, and has already carried out 1,288 clinical consultations , 81 transfers for medium and high complexity care, and 225 home visits . 

The teams operate both in indigenous territories and in the municipalities of Dourados and Itaporã, supporting local management, together with the Mato Grosso do Sul State Health Secretariat, reorganizing care flows, expanding active case finding, and guaranteeing assistance, health education, and psychosocial care.

Fiocruz mobilized the shipment of pain medication, reinforcing its ability to meet local demand due to the epidemic.

To expand response capacity, the Ministry of Health authorized the emergency hiring of 50 Endemic Disease Control Agents (ACEs). Of these, 20 have already been trained and will enter the field this Friday (3), while another 30 will begin training to work from Monday (6).

In the field of vector control, actions were intensified with the mobilization of approximately 95 professionals , including Community Health Agents and Indigenous Sanitation Agents (AISAN). Between March 9 and 16, 4,319 properties were inspected , of which 2,173 received treatment , identifying 1,004 breeding sites of the Aedes aegypti mosquito , mainly in water storage containers, solid waste, and tires.

Actions were also taken to control the spread of insecticide using ultra-low volume (ULV) methods, including three cycles of vehicle-mounted ULV application and backpack spraying in 43 high-traffic areas, such as schools and health units. The volunteer effort to remove breeding sites mobilized approximately 100 people and resulted in the collection of four dump truckloads of waste.

Vector control will be reinforced with support from the Ministry of Defense. Currently, 40 Brazilian Army soldiers and five vehicles are already in the area , expanding the operational capacity of the mosquito control efforts.

The Ministry of Health also sent 1,000 Larvicide Dissemination Stations (LDSs). Of the first 300 units, 150 have already been installed in priority neighborhoods, with expansion planned for other regions of the municipality.

Through Funai (National Indian Foundation), actions are also underway to provide direct support to indigenous communities in Dourados, focusing on food security and access to water. 

The distribution of 6,000 food baskets is planned , in three stages between April and June, in coordination with the Ministry of Social Development (MDS), the National Supply Company (Conab), the Special Secretariat for Indigenous Health (Sesai), and Civil Defense. The expansion of the water supply system in the Jaguapiru and Bororó villages has also been authorized to guarantee access to potable water and improve the sanitary conditions of the indigenous communities.

Epidemiological scenario

The most recent epidemiological surveillance data, referring to April 2nd, indicates that the region has registered 2,812 notifications of chikungunya, with 1,198 confirmed, 430 discarded, and 1,184 still under investigation. The highest concentration of cases is in indigenous villages, where 822 cases were confirmed—68.6% of the total confirmations in the region. 

So far, five deaths have been confirmed in Dourados, all among the indigenous population of the municipality.

To strengthen the coordination of actions, the Ministry of Health established a Situation Room in Brasília on March 25th, with permanent meetings to monitor the situation and integrate decisions between technical teams and managers.

Within the indigenous territory, the work is carried out in a coordinated manner between the Ministries of Health, Indigenous Peoples, Integration and Regional Development, Defense, Social Development, Funai (National Indian Foundation), and the Special Indigenous Health District of Mato Grosso do Sul (DSEI-MS), which has 210 Indigenous Health Agents (AIS) and 150 Indigenous Sanitation Agents (Aisan), in addition to logistical support with 91 pickup trucks, 6 vans, and 1 truck.

The actions also include training for health professionals in the municipal and indigenous networks, aligning clinical protocols for diagnosis and proper management of the disease, as well as health education activities in schools and communities. There are also plans to send prevention messages via WhatsApp to more than 234,000 residents , in Portuguese and with translation into indigenous languages.

The response also includes improving the quality of care, with the implementation of the national chikungunya protocol and training of teams for early identification of severe cases and appropriate clinical management.

Source: 

Link: https://www.gov.br/saude/pt-br/assuntos/noticias/2026/abril/governo-do-brasil-intensifica-resposta-integrada-e-mobiliza-forca-tarefa-para-enfrentar-emergencia-sanitaria-em-dourados-ms-2

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#USA, New York State Department of Health Confirms First Locally Acquired Case of #Chikungunya in #NewYork State (DoH)

 

ALBANY, N.Y. (October 14, 2025) — The New York State Department of Health today announced that a case of locally acquired chikungunya has been confirmed in New York State. Laboratory testing at the Department's Wadsworth Center confirmed the case in Nassau County on Long Island. This marks the first locally acquired case of chikungunya reported in New York State. No locally acquired cases have been reported in the U.S. states and territories since 2019.

An investigation suggests that the individual likely contracted the virus following a bite from an infected mosquito. While the case is classified as locally acquired based on current information, the precise source of exposure is not known. The Aedes albopictus mosquito, known to transmit chikungunya, is present in parts of downstate New York. Local transmission can occur when an A. albopictus mosquito bites an infected traveler, becomes infected and bites another person. The disease cannot be spread directly from one person to another.

"Our Wadsworth Center has confirmed this test result, which is the first known case of locally acquired Chikungunya in New York State. Given the much colder nighttime temperatures, the current risk in New York is very low." State Health Commissioner Dr. James McDonald said. "We urge everyone to take simple precautions to protect themselves and their families from mosquito bites."

Chikungunya is a mosquito-borne disease most common in tropical and subtropical regions. Symptoms include fever and joint pain, headache, muscle pain, joint swelling, or rash. The illness is rarely fatal and most patients recover within a week, though some may experience persistent joint pain. People at higher risk for severe disease include newborns infected around the time of birth, adults aged 65 and older, and individuals with chronic conditions such as high blood pressure, diabetes or heart disease.

In 2025, there have been three additional chikungunya cases outside New York City that were all linked to international travel to regions with active chikungunya infections. Routine mosquito testing conducted by the Department's Wadsworth Center and the New York City Department of Health and Mental Hygiene (DOHMH) has not detected chikungunya virus in any New York mosquito samples to date.

Mosquito activity in New York is declining as cooler fall temperatures begin. The Department reminds all New Yorkers to take precautions to reduce the risk of mosquito bites:

-- Use EPA-registered insect repellents

-- Wear long sleeves, long pants and socks outdoors when possible

-- Remove standing water around homes, such as in flowerpots, buckets and gutters

-- Repair or patch holes in window and door screens to keep mosquitoes out

(...)

Source: Department of Health, https://www.health.ny.gov/press/releases/2025/2025-10-14_chikungunya.htm

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Re-emergence of #chikungunya virus in #China by 2025: What we know and what to do?

 

Abstract

In July 2025, China witnessed its most significant chikungunya virus (CHIKV) outbreak since 2010. As of August 1, with over 6,000 cases reported in Foshan city, Guangdong Province. Although the clinical manifestations have been relatively mild, the rapid transmission within communities warrants our attention. In this context, we emphasize our current knowledge and the necessary actions to take. Specifically, we identify critical gaps in CHIKV control efforts and assess the effectiveness of current measures. These include vector management strategies, viral genomic surveillance, the deployment of newly approved vaccines, and the development of antiviral agents. Overall, to effectively control the epidemic of CHIKV, we require a comprehensive and multifaceted strategy for its prevention and management.

Source: PLoS Pathogens, https://journals.plos.org/plospathogens/article?id=10.1371/journal.ppat.1013556

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#Chikungunya virus disease - #Global #situation (#WHO D.O.N., Summary, Oct. 3 '25)

 

Situation at a glance

In 2025, a resurgence of chikungunya virus (CHIKV) disease was noted in a number of countries, including some that had not reported substantial case numbers in recent years. 

Between 1 January and 30 September 2025, a total of 445 271 suspected and confirmed CHIKV disease cases and 155 deaths were reported globally from 40 countries, including autochthonous and travel imported cases. 

Some WHO Regions are experiencing significant increases in case numbers compared to 2024, although others are currently reporting lower case numbers. 

This uneven distribution of cases across regions makes it challenging to characterize the situation as a global rise, however, given the ongoing outbreaks reported globally in 2025, the potential for further spread remains significant. 

CHIKV disease can be introduced into new areas by infected travelers and local transmission may be established if there is the presence of Aedes mosquito and a susceptible population. 

The risk is heightened by limited population immunity in previously unaffected areas, favorable environmental conditions for vector breeding, gaps in surveillance and diagnostic capacity, and increased human mobility and trade. 

Strengthening disease surveillance, enhancing vector surveillance and control, and improving public health preparedness are essential to mitigate the risk of further transmission. 

Prior to 2025, current or previous autochthonous transmission of CHIKV has been reported from 119 countries and territories. 

A total of 27 countries and territories across six WHO regions have established competent populations of Aedes aegypti mosquitoes but have not yet reported autochthonous CHIKV transmission. 

Additional countries have established populations of Aedes albopictus mosquitoes, which can also transmit CHIKV, and in which transmission efficiency is enhanced for CHIKV lineages with the E1 226V mutation. 

The presence of these vectors poses a continuous threat of chikungunya introduction and spread in previously unaffected areas. 

Increased CHIKV transmission is driven by multiple factors that include: 

- the expanded geographic distribution of Aedes mosquitoes related to transportation in conveyances and 

- climate change, 

- unplanned urbanization, 

- poor water management, and 

- weakened vector surveillance and control. 

CHIKV disease typically causes high population attack rates. In smaller settings such as islands, the transmission dynamics can be temporarily interrupted once a proportion of the population becomes infected and subsequently immune. 

In larger populations however, where enough individuals remain immunologically susceptible, transmission can persist over time, leading to sustained outbreaks. 

These outbreaks often place a significant burden on healthcare systems due to the number of affected individuals. 

Countries differ in their ability to detect and report chikungunya and other vector-borne diseases, with many outbreaks identified only retrospectively, hindering effective public health responses. 

Early detection of cases, particularly in persons at risk for severe CHIKV disease, and timely access to appropriate medical care are essential for minimizing clinical complications and reducing mortality. 

The variation in distribution of cases across regions highlights the importance of continued investment in surveillance, preparedness, and response capacities to address evolving regional dynamics. 

WHO continues to call on all countries to strengthen their healthcare and laboratory systems to enable rapid detection, timely reporting, and effective response to chikungunya outbreaks.

(...)

Source: World Health Organization, https://www.who.int/emergencies/disease-outbreak-news/item/2025-DON581

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#Syndromic approach for rapid #detection and differentiation of #human pathogenic #alphaviruses

 

Highlights

• Most vector-borne viruses like alphaviruses are not included in routine diagnostics

• Lack of testing results in misdiagnoses and underdetection

• A new multiplexed real-time PCR assay detects all human pathogenic alphaviruses

• The new multiplex assay is more sensitive than available tests and highly specific

• The multiplex test can be applied broadly for diagnostics and molecular surveillance

Abstract

Background

Knowledge of epidemiology, pathogenesis, and public health burden is scarce for many arthropod-borne viruses (arboviruses). Insufficient knowledge is partly due to lack of exhaustive laboratory diagnostics due to resource limitations. Among arboviruses, arthritogenic and encephalitogenic alphaviruses are globally widespread, can cause severe disease, and can co-occur regionally.

Objectives

We developed and validated a multiplexed real-time reverse transcription-PCR assay for the detection of all alphaviruses commonly causing human disease except Barmah Forest virus.

Study design

The assay combines five antigenic complex-specific assays and one Chikungunya virus-specific assay in a single parallelized reaction.

Results

Comparisons with previously published PCR-based protocols for broad alphavirus detection using 20 different human-pathogenic alphaviruses revealed a significantly higher sensitivity of the new multiplexed assay (Fisher’s exact test, p<0.0001). Detection limits with the new assay ranged from 0.83 cps/μl of extracted O’nyong-nyong virus to 33.05 cps/μl of extracted Western equine encephalitis virus. Antigenic complexes could be clearly differentiated by reactivity, Ct values (T-test, p<0.0025) and signal intensities (T-test, p<0.0001), even when testing high alphavirus concentrations potentially capable of causing false-positive PCR results. Testing of high-titred cell culture supernatants of eight important non-alphaviral arboviruses, of 4,308 serum samples collected from febrile patients in Benin and Peru, of seven CHIKV positive diagnostic samples from Brazil, and of non-targeted alphaviruses confirmed excellent diagnostic performance by the new assay, including improved detection of Mayaro and Venezuelan equine encephalitis virus in clinical specimens.

Conclusions

Short turn-around time, applicability in resource-limited settings, antigenic complex determination, and higher sensitivity compared to previously available tests make the new assay a useful tool for alphavirus surveillance and routine patient diagnostics.

Source: Journal of Clinical Virology, https://www.sciencedirect.com/science/article/pii/S1386653225001143?dgcid=rss_sd_all

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Serologic #Surveillance for #Orthoflaviviruses and #Chikungunya Virus in #Bats and #Opossums in #Chiapas, #Mexico

Abstract

We performed serologic surveillance for selected arthropod-borne viruses (arboviruses) in bats and opossums in the Lacandona Rainforest, Chiapas, Mexico, in 2023–2024. Sera were collected from 94 bats of at least 15 species and 43 opossums of three species. The sera were assayed by the plaque reduction neutralization test (PRNT) for antibodies to eight orthoflaviviruses (dengue viruses 1–4, St. Louis encephalitis virus, T’Ho virus, West Nile virus, and Zika virus) and one alphavirus (chikungunya virus; CHIKV). Twelve (12.8%) bats and 15 (34.9%) opossums contained orthoflavivirus-specific antibodies. One bat (a Jamaican fruit bat) was seropositive for Zika virus, and 11 bats contained antibodies to an undetermined orthoflavivirus, as did the 15 opossums. All bats and most opossums seropositive for an undetermined orthoflavivirus had low PRNT titers, possibly because they had been infected with another (perhaps unrecognized) orthoflavivirus not included in the PRNTs. Antibodies that neutralized CHIKV were detected in three (7.0%) opossums and none of the bats. The three opossums had low CHIKV PRNT titers, and therefore, another alphavirus may have been responsible for the infections. In summary, we report serologic evidence of arbovirus infections in bats and opossums in Chiapas, Mexico.

Source: Viruses, https://www.mdpi.com/1999-4915/17/5/590

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