Tag Archives: Mosquito

99-Million-Year-Old Amber Contains the Earliest Mosquito Larvae

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This newly discovered fossil, preserved in amber from Myanmar’s Kachin region, marks the first instance of a mosquito larva found in amber and represents the earliest immature mosquito of the Mesozoic era, designated as a new genus and species: Cletosabetes primaevus. This discovery strongly suggests that the mosquito family Culicidae has its origins in the Jurassic period and indicates that its larval structure has remained largely unchanged for at least the past 99 million years.

Larva of Cletosabetes primaevus. Image credit: Amaral et al., doi: 10.1016/j.gr.2025.09.011.

Mosquitoes comprise a vast group of insects, with over 3,727 known species alive today.

Although small, they are quite noticeable and widely distributed, playing significant roles in ecosystems, human history, and both human and veterinary health.

To date, 31 species of mosquito fossils have been documented. These ancient mosquitoes closely resemble modern species and are classified within the same genus as their modern counterparts.

“The earliest known mosquito fossils are adults, also found in amber dating back about 99 million years,” stated Dr. Andre Amaral from Ludwig-Maximilians-University of Munich and his team.

“Given their morphological distinctions from living species, they are considered part of a separate group, Burmaculicinae, representing an extinct lineage within Culicidae.”

The authors note that Cletosabetes primaevus belongs to the Sabetini group, which includes existing species.

Similar to the larvae of current Sabetini species, this new species’ larvae likely thrived in small water bodies.

“According to currently uncovered fossils, the evolutionary roots of mosquitoes are believed to be in the Jurassic period, roughly 201 to 145 million years ago,” the researchers remarked.

“Molecular phylogeny analyses yield varying conclusions, from the Triassic to Jurassic periods.”

“Our research strongly indicates that mosquitoes had already diversified during the Jurassic period, with their larval structure remarkably consistent for nearly 100 million years.”

“This finding challenges previous notions regarding the early evolution of this insect group and offers fresh insights into its evolutionary ecology.”

A segment of amber containing Cletosabetes primaevus larvae was sourced from the Kachin Amber Mine in Myanmar’s Hukaung Valley.

This amber dates back to the Late Cretaceous, about 98.79 million years ago.

“This fossil stands out as the larva closely resembles modern species. Unlike other mosquito fossils from this period, it displays distinct morphological features no longer found in today’s species,” Dr. Amaral explained.

A paper detailing Cletosabetes primaevus was published in this month’s edition of Gondwana Research.

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Andre P. Amaral et al. 2025. The first fossilized mosquito larva discovered in 99-million-year-old amber illuminates the evolutionary history of mosquitoes (Diptera: Mosquitoidae). Gondwana Research 150: 154-162; doi: 10.1016/j.gr.2025.09.011

Source: www.sci.news

The “mosquito growth crisis” in Las Vegas is a “ticking time bomb”

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Las Vegas – Once believed to be inhospitable for mosquitoes, this city proves the opposite is true.

While these pests typically thrive in tropical, humid environments, their population has surged in the Las Vegas Valley in recent years due to various factors.

Urban development, climate change, insecticide resistance, and genetic adaptation have all created a more conducive environment for these insects in southern Nevada.

Las Vegas isn’t alone in its struggle against these pests; warm temperatures and shifting weather patterns are extending the habitats where mosquitoes can breed across the southwestern United States and beyond.

Besides being a nuisance, mosquitoes also pose a significant risk of mosquito-borne diseases like dengue and West Nile virus to Las Vegas and Clark County.

This situation has taken many by surprise.

“It’s not incorrect to say that mosquitoes shouldn’t thrive in desert conditions, but it’s evident that certain species present in Clark County have adapted to the local environment.”

“Time Bomb”

Among the species found in Clark County are the Culex mosquito, known to carry West Nile virus, and the Aedes aegypti mosquito, a primary transmitter of dengue. Researchers at UNLV have also identified resistance to insecticides in local mosquito populations.

According to Messenger, “It’s a time bomb that’s been ticking for a while.”

She is particularly concerned about Las Vegas’s vulnerability to mosquito-borne diseases. Dengue fever cases are on the rise in North and South America, with more than 13 million cases reported across the continent in 2024, as noted by the CDC.

“Las Vegas receives over 48 million visitors from around the world every year,” Messenger remarked. “Local transmission can start with just a single mosquito bite.”

Last year, 26 cases of West Nile virus were reported in the city. According to the Southern Nevada Health District, 2019 had the largest outbreak, but a record number of mosquitoes tested positive for the virus in and around Las Vegas in 2024.

While some mosquitoes have tested positive for the virus this year, the public health department has not identified any human cases so far. Messenger indicated that specific factors from previous years complicate their understanding of the situation.

“We see many overlapping factors, but it’s challenging to isolate them,” she said. “There are these bumper years and then none at all, making predictions difficult.”

The Southern Nevada Health District has been monitoring mosquitoes since 2004, keeping detailed records that show the types of mosquitoes present in the Las Vegas Valley and their associated diseases.

One striking trend has been the rapid increase in Aedes aegypti mosquitoes, first spotted in Las Vegas in 2017, according to Vivek Raman, an environmental health supervisor for the Southern Nevada Health District.

“Relentless Biting” Spreads

“In 2017, we found this mosquito in just a few zip codes,” Raman noted. “A few years later, it expanded to six, then twelve, and now it has appeared in 48 different zip codes throughout the valley.”

These insects not only spread dengue fever but are also a significant nuisance.

“The Aedes aegypti is an extremely aggressive daytime mosquito,” Raman explained. “Their bites are relentless.”

Unlike Culex mosquitoes, they prefer to breed near larger water sources, such as neglected swimming pools, dark corners, and detention ponds.

“One of the reasons for their rapid spread is their ability to lay eggs in small containers, like children’s toys, tires, or wheelbarrows,” Raman added. “Just a few inches of water are enough.”

Urban development in Las Vegas has also redirected mosquito populations. According to Messenger, golf courses, artificial lakes, and other irrigation methods have transformed the Nevada desert into an inviting habitat for mosquitoes.

Climate change is another contributing factor and is under active investigation by Messenger and other scientists. Higher temperatures are broadening the areas where mosquitoes can thrive. Warm air can hold more moisture, leading to increased humidity and rainfall—all ideal for mosquito breeding.

While it’s not entirely clear how local environmental aspects interact with shifting climate trends to impact mosquito populations, the potential consequences are significant.

“Las Vegas serves as a case study for how climate change may manifest in other regions globally,” Messenger stated. “We’re witnessing record temperatures and increasingly erratic precipitation patterns. This is predictive of what much of the world may look like in the next 15-25 years.”

The implications for urban mosquito populations remain uncertain, but current trends show no signs of abating.

Health districts in southern Nevada are engaging in public outreach to help residents identify and manage mosquito breeding sites around their homes, along with strategies to prevent bites. To effectively address mosquito populations and associated public health risks, comprehensive efforts from local governments are essential, according to Messenger. Right now, this level of coordination is lacking in Las Vegas.

“We have private pest control companies, and some work is being done around wetlands, but what we lack is a centralized and coordinated reduction effort across multiple jurisdictions,” Messenger explained.

That absence of coordinated action has contributed to mosquito populations becoming increasingly resistant to insecticides. Ongoing monitoring is necessary to determine which chemicals are safe to use around humans and to evaluate the effectiveness of insecticides and pesticides to prevent mosquitoes from developing immunity.

Looking ahead, Messenger emphasized that prevention and control will be vital to protecting both Las Vegas residents and the many visitors from around the globe.

“Ultimately, this situation is entirely preventable,” she asserted. “No one in southern Nevada, including Clark County, should suffer mosquito bites or risk contracting any virus.”

Source: www.nbcnews.com

West Nile Virus Identified in British Mosquito for the First Time

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A fragment of the virus has been identified in Aedes aegypti mosquitoes in Nottinghamshire, UK

IMV/ISTOCKPHOTO/GETTY IMAGES

The West Nile virus, marking the first potential fatal mosquito-borne disease in the UK, has been identified for the first time.

The UK Health Security Agency (UKHSA) has announced that its research collaboration with the Animal and Plant Health Agency has Afa successfully identified a “fragment” of the virus in Aedes aegypti mosquitoes collected from the marshlands along the Idol River in Nottinghamshire in July 2023, indicating that these insects are carriers of pathogens.

According to Alanfolly from Apha, the virus was discovered somewhat by chance during routine testing by his team. He notes that further screenings will take place around that area later this year. Interestingly, Nottinghamshire typically does not fall into Afa’s primary testing regions, which are mostly centered in southern and eastern England, where warmer climates increase the likelihood of infections such as West Nile.

Humans and horses can become infected with the West Nile virus through mosquito bites. Approximately 20% of infected individuals exhibit symptoms such as fever, headaches, body aches, vomiting, and diarrhea. In rare instances, the virus can lead to severe inflammation of the brain and spinal cord, which can be fatal. Currently, there are no approved vaccines for humans.

UKHSA has reported the virus’s presence only in two mosquito samples, with no current evidence suggesting that humans or horses are infected in the UK. The organization’s assessment indicates a very low risk to the public, but healthcare professionals are advised to test encephalitis patients for unexplained causes.

“This is the first identification of the West Nile virus in British mosquitoes, though it doesn’t come as a surprise given the virus’s ongoing spread across Europe,” stated Meera Chand from UKHSA.

The West Nile virus has been increasingly observed in Africa, Europe, and North America. In Europe, recent years have seen its northern spread, reaching the Netherlands in 2020.

Factors contributing to the spread of the West Nile virus include elevated spring and summer temperatures, summer droughts, and milder winters, all of which are becoming more prevalent in Northern Europe. Although APHA has not detected the West Nile virus in mosquitoes or birds for 2024, the recent warm weather in the UK could change that. “We had an unusually warm May,” Folly noted. “If there is another case, we may see it in the coming weeks. This is just the beginning; more cases could follow.”

British researchers have been vigilant for the West Nile virus since 2020 when a related mosquito-borne virus (USUTU) was first found in London. The West Nile virus shares similar transmission characteristics with USUTU and requires comparable environmental conditions.

“I wouldn’t be surprised at all,” stated Matthew Baylis from the University of Liverpool. “I’ve been expecting this to happen every year. I believe that the West Nile virus will eventually be detected in the UK.”

He suggested that the virus likely arrived in the UK via birds and is probably circulating among various mosquito species in the region. However, he reassured that there is no immediate cause for alarm. “The risk remains low for most people. While a few horses are susceptible to West Nile disease, it’s quite rare,” he added.

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Source: www.newscientist.com