Health threats in 2023

Vector-borne diseases transmitted by insects and ticks posed public health threats in 2023. Diseases like malaria, dengue, chikungunya, Zika, West Nile virus, and Lyme disease continued to impact communities around the world throughout the year. More action and vigilance will be needed in 2024 to control these persistent risks.

In 2023, malaria remained one of the top vector-borne disease killers globally. Over 200 million malaria cases were reported, leading to an estimated 600,000 deaths. Sub-Saharan Africa endured most of the burden though Southeast Asia, South America, and other regions were impacted too.

Controlling the spread of malaria requires addressing socioeconomic risk factors and improving coordinating surveillance, diagnostic testing, vector control, and therapeutic measures across endemic areas.

Dengue also persisted as a major mosquito-borne viral threat, with up to 100-400 million infections estimated annually in over 125 countries. Severe dengue can lead to fatal haemorrhagic complications.

In 2023, many Southeast Asian countries – including India, Pakistan, Nepal, Bangladesh, Philippines, and Vietnam – continued having large seasonal dengue outbreaks that overburdened their health systems.

With global warming, dengue risks have increased geographically, putting over half the world’s population at risk. Integrating preventive measures like public education and mosquito control and developing an effective but affordable tetravalent vaccine is key for the future.

Chikungunya, another painful mosquito-borne viral disease, saw outbreaks in 2023 across parts of Africa, Southeast Asia, and the Western Pacific region. Global spread is furthered by infectious travellers. There is no cure or commercial vaccine yet. Better surveillance and bite prevention are primary means to combat this debilitating disease.

Zika virus, also mosquito-transmitted, has been a threat since its massive 2015 outbreak spread across South America, alarming the world over its new risk of severe congenital disabilities.

In 2023, Zika continued circulating in some regions, causing sporadic outbreaks while heralding dangers of future resurgence, especially across warmer regions. Travel warnings for pregnant women are still advised for Zika-affected areas in Latin America and Asia-Pacific. Continued vigilance and development/deployment of rapid diagnostics and a Zika vaccine can help counter its re-emergence and protect newborns in the coming years.

The West Nile virus represented another persistent mosquito-borne threat in 2023, causing regular seasonal outbreaks across North America and Southern Europe associated with human infections and deaths.

Over 300 deaths were recorded in Europe attributable to West Nile in recent years. The US has also endured over 50,000 cases and 2500 deaths cumulative since 1999, showing its firm endemic status. Warmer seasons see spikes, so surveillance and public education on mosquito bite precautions help reduce annual caseloads.

Lyme disease and other tick-borne diseases like Rocky Mountain spotted fever, anaplasmosis, and ehrlichiosis also plagued the US and Europe in 2023 as tick populations and habitats expanded, increasing human exposure.

Lyme remains the most common vector-borne illness in the US, with over 450,000 Americans diagnosed probably annually. Lyme cases have risen in recent years as suburban habitats favour ticks and block wildlife migration that helps control their populations naturally.

Land use policies and tick control measures are needed to interrupt tick-to-human transmission of bacteria that, if untreated, can have chronic effects like arthritis, carditis and neurological impairment. Continued awareness of tick bite prevention and promptly identifying/removing attached ticks remains essential to reducing personal risk.

Major strides in controlling vector-borne diseases globally remain an unfinished agenda, needing expanded effort and resources in 2024 and beyond. Mosquito and tick-transmitted diseases still impose an annual burden of over one million deaths and 700 million illnesses despite modern public health measures and diagnostics.

Much work lies ahead to implement integrated surveillance and sustainable vector control programmes. Traveller education also remains key to curbing imported outbreak threats. Vaccines may help eliminate or drastically reduce infections and mortality associated with persistent vector-borne diseases in the coming decade.

But for now, vigilance and risk-lowering actions by households and community public health authorities represent frontline defence against their expanding impacts, driven by increasing temperatures, urbanization, deforestation and climate disruptions across many vulnerable disease-endemic regions worldwide.

This complex challenge requires sustained countermeasures to detect, characterize, and snuff out blossoming outbreaks quickly before they cause unnecessary suffering and universal health threats.

The writer is an assistant professor at the Institute of Public Health, Lahore. He can be reached at: uzair@hsa.edu.pk