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RNZ News
22-07-2025
- Health
- RNZ News
'Biggest number we've had': Pacific dengue cases highest in a decade
The Asian tiger mosquito is one of the vectors responsible for transmitting dengue fever. Photo: SCIENCE PHOTO LIBRARY Dengue cases in the Pacific are at their highest since 2016, with nearly 19,000 people affected, the World Health Organisation (WHO) says. The new figures come as multiple nations in the region grapple with outbreaks and surging case numbers. Just last week, Samoa confirmed a second child with the disease had died this year. Overall, nine dengue-related deaths have been reported across the region. WHO's Pacific Techincal Support director Dr Mark Jacobs told Pacific Waves that July regional data showed the number of suspected dengue cases was at 18,766 - the highest since 2016. "We've been seeing a gradual increase in dengue in the Pacific for at least the last couple of decades. But looking at the last 10 years, what we tend to see is peaks in some years and then lower levels in other years. "This year, so far, we're up to two more than 18,000 suspected cases of dengue….that's the biggest number that we've had certainly in the last 10 years. Of those, 12,040 were laboratory-confirmed cases. Jacobs said the high case numbers were due to a range of factors, including the movement of people between Pacific nations. "The virus that causes dengue fever basically lives in people and lives in mosquitoes. And so for a lot of the…smaller Pacific countries, they haven't got enough people for the virus to keep on circulating all the time. "What tends to happen in those…Pacific countries is, if there's an outbreak somewhere else in the Pacific, or somewhere where there's people moving to and from, someone might come into that country from another country [where] they've already been infected…and bring the virus back." Climate change and shifting weather patterns in the region also increased the risk around dengue spread, he said. The lack of understanding around dengue hot-spots was another risk factor. "It's actually most common in urban settings and semi-urban settings, so towns and villages where there's quite a few people living. [That's where] the mosquito is very comfortable living - in and around people's houses." A breakdown of the WHO July data, showed spread of the disease had been highest in Fiji, which had 13,702 suspected cases, followed by Tonga (2087) and French Polynesia or Mā'ohi Nui (1079). The data also showed numbers appeared to have peaked in March. However, in recent months, there had been a resurgence in spread of the virus. In particular, it had been found in previously unaffected nations like American Sāmoa, Nauru and Tuvalu. Jacobs said the four different strains of dengue also added to challenges around preventing spread and illness. This was because immunity to dengue was generally dependent on individual strains. "If you've been infected in the past with type one dengue, then you're unlikely to get that sort of dengue again," he said. "But if…a different strain of the of the dengue virus comes into the country some years later - dengue type two for instance - then all the people who've been infected with type one before, who've been protected against getting type one again, they could all get type two." Jacobs said that transmission pattern often triggered big outbreaks. It also contributed to more severe illness from dengue. "If somebody's had dengue more than once, in other words, if they've had it with a couple of the different strains a few years apart, they're the people most likely to get really, really severely ill with dengue. "And so we see more of the severe dengue, more complications of dengue in those people." In Samoa, the acting director-general of health Tagaloa Dr Robert Thomsen said the government was prioritising mosquito spraying of areas and buildings where people gathered in its response. These included schools and sites like the Victim Support centre and National University of Sāmoa, he said. Tangaloa confirmed the recent dengue-related death was an eight-year-old girl. She died on Sunday 13 July. Misiafa Lene, 12, died in April after contracting dengue. As of 13 July, the number of laboratory-confirmed dengue cases was 1276 in Samoa. "For the past three weeks - excluding this week - we've seen an increase of about 100 confirmed cases per week," Tagaloa said. "Our biggest challenge at the moment…is the paediatric age group - children below 15 years of age. [They] appear to be the ones that are mostly affected."
Times of Oman
22-06-2025
- Science
- Times of Oman
How dangerous are invasive insects in Europe?
Berlin: As winters become milder due to climate change, insects normally found only in the tropics are starting to feel more at home across Europe. And the speed of travel and global trade is making it easier than ever for them to make the trip — in imported wood, potted plants or simply as stowaways. But these exotic newcomers aren't exactly welcome. Experts with the European Environment Agency told DW that invasive alien species, including insects, are a "major threat to native plants and animals in Europe and are one of the five major causes of biodiversity loss." Though tiny, these pests compete with native species for resources and destabilize fragile ecosystems already dealing with pollution, overexploitation and the effects of a warming planet. They're also a serious problem for humans, spreading disease, destroying crops and costing the EU an estimated €12 billion ($13.8 billion) per year in recovery and eradication expenses. Here are just a few of the invasive insects threatening Europe. Asian tiger mosquito (Aedes albopictus) The tiger mosquito, named for its distinctive white stripes, is native to the tropical and subtropical forests of Southeast Asia and was first spotted in Albania in 1979. It made its way over to Italy and France in the 1990s, and is now well-established across the Balkans, southern Ukraine, southwestern Russia and much of the Mediterranean region. But with its tough eggs and a new tolerance for cooler weather, it has also been spotted in Belgium, Germany and as far north as Sweden in recent years. The tiger mosquito thrives in urban environments, reproducing in standing water in places like flowerpots or gutters. This adaptability — along with a tendency to be active during the day — has made humans an easy target for the insect, which can feed on blood several times a day. Aside from being an itchy nuisance, those bites can transmit contagious human diseases like dengue, chikungunya and the Zika virus. Asian hornet (Vespa velutina nigrithorax) This stinging menace, originally from eastern Asia, first arrived in France in 2004. Also known as a yellow-legged hornet, it's slightly smaller than the native European variety, has an overall darker coloring and is active during the day. It has since spread to more than a dozen European countries, including Spain, Portugal, Belgium, Italy, Germany and the UK. It's not to be confused with the giant Asian hornet, also known as the "murder hornet" for its dangerous sting. Though being stung by the Asian hornet can be quite painful for humans, the greater risk is to food security and biodiversity, according to agricultural nonprofit CABI. The species preys on hundreds of crucial pollinators such as bumblebees, butterflies and flies. But its main target is the European honeybee, which pollinates more than 80% of Europe's crops and wild plants. A study published in the journal Science Of The Total Environment in March 2025 found that the hornet can kill up to 50 bees a day. The Asian hornet is one of 88 species on the EU's list of Invasive Alien Species of Union Concern, which requires member states to prevent the spread of the insect and eradicate it wherever possible. American ants (Solenopsis geminata, Solenopsis invicta, Solenopsis richteri, Wasmannia auropunctata) Also on the EU's most wanted list are four species of foreign ants: the tropical fire ant, the red imported fire ant, the black imported fire ant and the little fire ant. These tiny invaders were accidentally introduced from Central and South America, with the tropical fire ant first showing up in Europe as far back as the 1860s. With its painful sting which can cause an allergic reaction, these species rapidly displace other native ant populations and disrupt ecosystems and agriculture with aggressive feeding habits. A 2023 study at the Institute of Evolutionary Biology in Barcelona found that 7% of the European continent was a suitable habitat for the ant, and that's likely to grow as climate change increases their habitable range. Half of Europe's cities were already vulnerable to invasion — bad news, as these ants can also damage electrical equipment by chewing through wiring and causing short circuits. Brown marmorated stink bug (Halyomorpha halys) This extremely invasive pest from Asia is now widespread in France, Italy and Switzerland, but present across most of the continent. They are especially attracted to fruit, nuts and grapevines, but are just as happy munching on vegetables and other crops, like soy. In Italy, the stink bug caused an estimated €588 million in damage to fruit crops in 2019 alone. Farmers have traditionally fought back with insecticides, but researchers are also considering a more environmentally friendly method — pitting the stink bug against its natural enemy. The Samurai wasp (Trissolcus japonicus), another accidental introduction from Asia, is a parasite that lays its eggs inside the eggs of the brown marmorated stink bug. The wasp larvae feed on the stink bug egg, eventually killing it. Some researchers have cautioned that relying on another foreign insect to handle the problem might end up causing more ecological disruption. But a 2023 study led by CABI found that the wasp appeared to have little impact on most native insect populations. Asian longhorned beetle (Anoplophora glabripennis) Listed among the 100 world's worst invasive alien species by the International Union for Conservation of Nature, this beetle is a major threat to deciduous trees and shrubs. Adults feed on leaves, stems and twigs while larvae burrow into the trunk, slowly killing a tree within a few years. Urban trees, which help to cool cities, are especially vulnerable due to their proximity to ports; in the eastern US, where the beetle arrived in the 1990s, up to 35% of the trees in cities are at risk. The insects are often introduced in wood packaging, and have been found in France, Germany, Italy, Switzerland and Poland. But their populations are not yet widely established, and some eradication campaigns have been successful. Europe will have to learn to live with invasive species "Invasive alien insects often appear more difficult to manage than invasive plants or larger animals: They are small, mobile, reproduce rapidly, have short life cycles and often go unnoticed until the damage is done," said the EEA. While it's nearly impossible to completely eradicate an invasive insect species, the damage can be mitigated. Asian hornets have been kept at bay in some areas with special traps and by removing their nests, while researchers in Italy have recently used drones and artificial intelligence to detect and monitor stink bugs. Other methods involve stopping the insect at the source, for example by treating wooden packing with heat before shipping to kill the longhorned beetle. In some cases, it's as simple as clearing any standing water from your balcony or backyard, to stop the spread of mosquitoes. But the experts stressed that insects weren't necessarily any worse than other invasive plants and animals, noting that "each group — and each invasion case — comes with its own biological and ecological complexities."
