Climate change and globalization can create dangers of the spread of disease. A recent study in the Lancet (https://www.thelancet.com/journals/lanplh/article/PIIS2542-51962100132-7/fulltext) said that additional 1.5 billion would be at risk for just one disease, dengue fever because of climate change. For many mosquito-borne illnesses, there is no vaccine and little in the way of treatment as the infections are viral. Prevention is the key.
Kalorama addressed emerging infections in a recent report, Emerging Infectious Diseases (https://kaloramainformation.com/product/emerging-infectious-disease-diagnostics-markets-and-trends-2022/) Kalorama’s report lists 116 potential mosquito-borne disease. Zika was the most recent mosquito-borne disease breakout in the United States. While it did not reach pandemic levels, Zika threatened to damage the economy in some localities, such as the US Virgin Islands and Florida. 227 cases of the disease were reported in the United States.
“Urbanisation is an important driver of mosquito-borne disease transmission, because it enhances the creation of mosquito breeding sites via human-made containers, increases the likelihood of vector–human interactions because of higher population densities, and facilitates spatial spread through the movement of people and goods.”The Lancet
The search for the next large-scale emerging disease was on before the COVID-19 pandemic, and testing is essential any time a new pathogen emerges. Respiratory diseases, for instance, avian flu, were among those suggested by Kalorama Information and other outlets and medical associations as possibilities for the next threat in previous market research reports. But the threat to humans from infectious disease is not limited to respiratory conditions, the next large outbreak could very well be animal-borne or mosquito-borne. The report discusses scores of diseases, though only major diseases with significant revenues at the present time are covered in market analysis sections. This organization is needed because the history of emerging diseases shows that any one of these diseases could break out into a situation requiring control and testing. It is therefore important that a knowledge of the world disease threats of a very broad nature is established.
Among the mosquito-borne emerging diseases. Two are Rift Valley Fever and Saint Louis Encephalitis. There are others:
- Rift Valley Fever has been listed as a WHO disease of concern. Rift Valley fever (RVF) is a disease of domestic ruminants, caused by an arbovirus belonging to the Phlebovirus genus (Bunyaviridae family). Until 1975, RVF was regarded as an African animal disease. Human cases were rare and with mild clinical manifestations. Severe outbreaks with hemorrhagic fever cases and fatalities in humans were reported in South Africa in 1975, Egypt in 1977 and Mauritania in 1987. One of the most noticeable outbreaks occurred in East Africa in December 1997, when unexplained human deaths were reported in the north-eastern province of Kenya and southern Somalia. This epidemic was considered the most devastating in the region. In September 2000, RVF was detected for the first time outside the African continent, in Saudi Arabia and Yemen, leading to human deaths and major losses in livestock populations. In 2006–07 an outbreak was declared in Kenya. Tanzania and Somalia were affected later. Madagascar and South Africa were hit in 2007 and 2008. It produces high mortality rates in newborn ruminants, especially sheep and goats, and abortion in pregnant animals. Human infection by Rift Valley fever virus (RVFV) may result from contact with viraemic animals and their body fluids, and with their carcasses and organs including offal, during veterinary practices, necropsy, slaughtering and butchering.
- Saint Louis encephalitis (SLE) is a disease caused by the mosquito-borne Saint Louis encephalitis virus. The name of the virus goes back to 1933 when within five weeks in autumn an encephalitis epidemic of explosive proportions broke out in the vicinity of St. Louis, Missouri, and the neighboring St. Louis County. Over 1,000 cases were reported to the local health departments and the newly constituted National Institutes of Health of the United States was appealed to for epidemiological and investigative expertise. The previously unknown virus that caused the epidemic was isolated by the NIH team first in monkeys and then in white mice.Saint Louis encephalitis virus is related to Japanese encephalitis virus and is a member of the family Flaviviridae. This disease mainly affects the United States, including Hawaii. Occasional cases have been reported from Canada, Mexico and the Caribbean, including the Greater Antilles, Trinidad and Tobago, and Jamaica.
The life cycle of all mosquitoes have four stages, which are not incidental in controlling population. The first three are: egg, larva, pupa. These stages occur in water, and then an adult stage. The female mosquito (which is the mosquito that feeds on humans) lays the eggs directly on water or flooded surface areas. An egg can be ready to hatch in two days, but in dry enough areas can last a month, the egg then hatches into larva, begins to swim in the water. Then after two days to a week in a pupal stage, the adult mosquito emerges onto the water’s surface and flies away. Only the female mosquito takes blood which they usually require for her eggs to develop. Females in the adult stage begin feeding. In inland areas of the U.S. heavy rains and flooding can produce millions of mosquitoes some that can travel up to 50 miles from the breeding site.
Mosquitos have natural predators that collectively can exert some influence on reducing mosquito populations. However, with a very few exceptions, predators generally have little effect on reducing the mosquito population over a large area. Predators of mosquitos include: Bats , Birds, Goldfish, guppies, bass, bluegill and catfish prey on mosquito larvae. Frogs and Tadpoles, Turtles, Dragonflies, Damselflies and Spiders. Mosquitoes are found throughout the world and many transmit pathogens which may cause disease. Disease carrying mosquito species are found throughout the U.S., especially in urban areas and coastal or in inland areas where flooding of lowlands frequently occurs.
Disease prevention is dependent on local governments and even homeowners in some cases. Local mosquito control departments ascertain the numbers and types of mosquitoes in an area and the infections they may be spreading. Professionals share prevention information with the public and use multiple methods at the same time to kill mosquito larvae and adult mosquitoes. Professionals from local government departments or mosquito control districts develop mosquito control plans, perform tasks to control mosquito larvae and adult mosquitoes, and evaluate the effectiveness of actions taken. Methods can include eliminating mosquito larval habitats, applying larvicides to kill mosquito larvae, or spraying insecticides from trucks or aircraft to kill adult mosquitoes.