As Americans gathered for July Fourth celebrations last week, many endured sweltering heat as the planet set an unofficial record for the highest temperature in history, a record that has since been broken twice. The average global temperature has risen by about 1 degree Celsius since pre-industrial times and is rising continuously by more than 0.2 degrees every decade.
This has implications not only for human activities, but also for the geographic distribution of animals – e.g. B. Mosquitoes and ticks – which can transmit a number of infectious diseases, including malaria and dengue fever. Climate change is likely due to the resurgence of certain diseases previously thought to be eradicated in the United States.
Female Anopheles albimanus mosquito, covered in blood, feeding on human host, 2005. Image … [+]
Malaria Transmission in the Southern United States
When you think of malaria, you probably associate the disease with equatorial locations in Central America, Africa, and Asia. However, many are surprised to learn that malaria was endemic in the temperate regions of the United States in the late 19th century and only after the establishment of a national program in 1947 was local transmission of the disease eradicated. However, with rising temperatures, increasing international travel and increasing urbanization, conditions are favorable for disease recurrence. In fact, the Centers for Disease Control and Prevention (CDC) recently reported seven cases of locally acquired malaria in Texas and Florida. This is the first time non-travel-related malaria has been diagnosed in the country in over 20 years, sparking alarm among doctors and public health officials.
Why should this be a concern? Malaria – caused by the parasite, plasmodium – can be a serious and life-threatening illness. Globally, 240 million cases occur each year, with more than 600,000 deaths reported. Fever, headache, body aches, and vomiting/diarrhea may occur in infected individuals. Because there has been no endemic transmission of malaria in the US for several decades, there is no established population level immunity. This can ease future outbreaks and potentially increase the severity of cases when they do occur.
Dengue virus is expected to increase in prevalence
It is estimated that approximately 400 million cases of dengue fever occur each year, resulting in nearly 36,000 deaths worldwide. Dengue fever – also known as broken bone fever due to the severe pain in the limbs that occurs – is a viral infection that is transmitted through the bite of a mosquito aedes Genus. Although most cases are mild and resolve without complications, serious illness can develop, potentially leading to hemorrhagic fever, shock, and death.
Although travel-related dengue fever is relatively common in the United States, local transmission has been rare in recent decades. However, endemic diseases have been identified in several states and US territories, including Florida, Texas, Arizona and Puerto Rico. In 2022, 57 cases of locally acquired dengue fever were reported in Florida, and an outbreak occurred in Puerto Rico with over 800 cases. In 2015, the state of Hawaii reported 200 cases of local transmission. These figures indicate a rising incidence of the disease in the United States as the spread of the transmissible mosquito vector increases.
DHAKA, BANGLADESH – AUGUST 18: Dengue patients are treated at Shaheed Suhrawardy Medical College and … [+]
Vector-borne diseases are likely to become more common
Malaria and dengue fever are just two vector-borne diseases showing signs of resurgence in the United States. As climatic and environmental factors drive the increased spread of mosquitoes and ticks, the prevalence of other infectious diseases such as Powassan virus, Zika virus, and Chikungunya virus could also increase.
So what can you do to protect yourself and others from these diseases? When outdoors, use insect repellent first and, if possible, wear long pants when walking through tall brush and grass. Second, remove standing water near your home, e.g. B. in bird baths, old tires or plant pots. Standing water is a breeding ground for mosquitoes and promotes the spread of diseases such as malaria. And if you’re exposed to mosquitoes or ticks and then develop a high fever, body aches, or a rash that doesn’t go away within a few days, see a doctor.
There are several reasons to urgently address the climate crisis, and the increasing spread of vector-borne diseases is an unfortunate finding to add to this growing list. We must act now.