Locally Acquired Malaria in the United States

Malaria, which affects half the globe, remains a dangerous infectious agent. A recent American study demonstrates a lack of knowledge of local epidemic causes. The main goal of this article is to investigate the Anopheles mosquito, the main vector, and to assess vector-borne disease preparation due to global warming. Overall, we wish to assess vulnerability to smaller malaria outbreaks here in the United States (US). The essay examines malaria’s prevalence globally and its implications in the US. The focus is on locally acquired malaria transmission, its effects, and preventative and control strategies. This article examines how global warming affects malaria transmission, diagnosis, and treatment within the US. Climate change affects malaria-carrying vector behavior and dispersal via changing temperature and humidity. As a result of climate change, multiple mosquito species with the potential to transmit malaria exist throughout the United States, and the vast majority of vector control groups are ill-prepared to deal with a vector-borne illness epidemic. The primary focus of this article is to evaluate our knowledge of the Anopheles mosquito vector as it is spread north of the US due to climate change. Furthermore, we will assess our ability to respond to malaria epidemics and how to reduce the susceptibility to localized malaria outbreaks and how to maintain efficient preventative and control efforts.


Introduction
Malaria, which is caused by parasite protozoa belonging to the Plasmodium genus, is one of the infectious illnesses that has the highest death toll globally.P. falciparum, which is mostly located in Africa and is responsible for the biggest number of fatalities, is one of these species [1].Additional species, such as P. vivax and P. knowlesi, also play a key role in the development of severe cases.In 1985, the World Health Organization (WHO) held its first conference on malaria, which was also the year when the phrase "severe malaria" was first introduced.Since then, this severe variety has become a prominent topic of investigation all over the world [1].
The fatality rate associated with severe malaria is affected by a wide range of factors, including the clinical status of the patient, the type of therapy, and the course of the illness.It is important to note that a patient's susceptibility owing to non-malaria-related variables such as age, co-infections, or weaker immune systems may lead to mortality regardless of the parasite that is infecting the patient [1].The mortality rate of severe malaria is more than 5%, while the mortality rate of uncomplicated malaria is less than 0.1%.In locations where there is a low rate of transmission, the disease is distributed consistently.However, in regions where there is a high rate of transmission, the risk of contracting the disease varies, especially among non-immune individuals such as small children and tourists from non-endemic areas [2].
While severe malaria may be characterized epidemiologically, the disease is often better described by its clinical symptoms and its effect on the body's vital organs.Patients with severe malaria frequently exhibit symptoms such as generalized weakness, impairment of consciousness, neurological problems, profound anemia with hemoglobin in urine due to acute kidney injury, respiratory distress, circulatory collapse or shock, hemorrhages, pulmonary edema, convulsions, jaundice, and other organs dysfunction [3].These symptoms are caused by severe anemia due to acute kidney injury.Clinical symptoms may present themselves alone or in combination.They are often associated with the sequestration of erythrocytes that carry the active parasites, which causes alterations in coagulation and cellular preservation [3], [4].
According to the World Health Organization [5], fewer than one per cent of cases with confirmed malaria progress to more severe forms of the disease.According to statistics by Murray et al. [6] & Hendriksen et al. [7], there Locally Acquired Malaria in the United States Naji were 619,000 deaths out of a total of 247,000,000 documented cases.Children under the age of five accounted for two-thirds of yearly mortality.Hospitalized children with severe malaria-induced anemia are especially at risk for greater post-admission death rates than other hospitalized children [8].
Plasmodium parasites, carried by mosquitoes and responsible for malaria, continue to pose a significant threat to human health all over the world [9].The global epidemiology of malaria and its particular ramifications inside the United States are carefully investigated in this article.This article focuses on instances of locally acquired malaria cases, their implications, and more comprehensive tactics for the prevention and control of the disease.

Materials and Methods
The research conducted by Hendriksen et al. [7] served as the basis for this investigation's methodology.The severity of severe falciparum malaria in parasitemic African toddlers was determined using the plasma falciparum histidine-rich protein 2 measure (PfHRP2).The following procedures were carried out in the course of our research.

Data Collection
Within the US, we reported information on the number of counties where anopheles mosquito is present.This contained information from the past as well as more contemporary developments.Furthermore, we reported the incidence of malaria cases that occurred over the year 2023 with a focus on locally transmitted cases within the US.We attempted to correlate the 2023 reported cases with data on the climate to assess possible relationships and trends.

Analysis of Climate Data
We reported climate models and data analysis tools to determine whether or not there was a trend in the temperature, rainfall, and humidity in locations where malaria was prevalent.The studies by Caminade et al. [10], and Li and Managi [11] were used in particular.Caminade et al. [10] reported a comparison of malaria distribution in 2014 and previous years with five different models.Li and Managi [11] looked at future malaria cases in light of possible climate change.

Analysis of the Malaria Incidence
We reported the incidence of malaria cases that occurred in 2023 year with a focus on the locally transmitted cases within the US.We attempted to correlate the 2023 reported cases with data on the climate in order to assess possible relationships and trends.

Epidemiology of Malaria Around the World
Malaria does not seem to have a consistent global distribution.Where malaria transmission is high, such as in sub-Saharan Africa, the illness has a significant impact on public health.High mosquito populations, insufficient healthcare, and socioeconomic difficulties all play a role in the disease's continued presence in these regions.However, low-transmission areas still see occasional outbreaks due to factors including international travel and migration [6], [9], [12].
The mosquito-borne illness malaria has been with humanity for a very long time.Ancient civilizations including Egypt, Greece, and Rome left historical records describing its terrible effects.Even the word "malaria" alludes to the old notion that the illness was spread by breathing in "bad air" from swampy regions [13].Significant advances in understanding the nature of the illness were not accomplished, however, until the 19 th century.The 20 th century was also pivotal, especially in the understanding of how malaria spreads.Antimalarial medications such as chloroquine and insecticides such as DDT were developed as World War II progressed in response to the devastating effects of malaria on military operations [6].
The World Health Organization [5] began an international effort to eliminate malaria in the middle of the twentieth century.While the project was somewhat successful, issues such as uneven coverage and the growth of mosquitoes resistant to insecticides prevented it from reaching its full potential [12].This led to a malaria resurgence in the later part of the century, shedding light on the many elements at play in the disease's distribution.This revival may be partially attributed to the emergence of drug-resistant strains and inadequate healthcare infrastructure in endemic regions [12].
With redoubled efforts, major advancements were made.The introduction of artemisinin-based combination treatments (ACTs) and the use of insecticide-treated bed nets have dramatically improved malaria prevention and treatment.The worldwide burden of malaria has been significantly reduced because of these measures and other global cooperation and focused projects.However, there are still problems to be solved [14].Changes in mosquito habitats and transmission patterns due to climate change, the persistence of medication resistance, and the inadequacy of healthcare facilities in endemic locations are all challenges.Research, innovation, and coordinated efforts by governments, non-governmental organisations (NGOs), and the international community are all being undertaken to lessen malaria's effects and pave the road for its ultimate eradication [14].
In the United States, preventing the spread from spreading locally is a top priority.Successful eradication efforts have reduced the prevalence of malaria in areas where it had been prevalent.However, foreign visitors pose a danger of reintroduction because of the world's increasingly mobile population.There are areas of the United States where the parasite-carrying Anopheles mosquito is found, and its distribution may be affected by weather patterns.Public health interventions in the United States are shaped in part by the worldwide epidemiology of malaria.Screening and treatment options for people returning from endemic regions may be informed by tracking the disease's global incidence and trends [15], [16].Furthermore, multinational cooperation aiming at lowering the global burden of illness may be informed by an awareness of the variables leading to the persistence of malaria in different places.

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Locally Acquired Malaria in the United States Fig. 1.Worldwide geography of malaria in the world [17].
According to the Centers for Disease Prevention and Control [17], there is an estimated 627,000 people died of malaria, mostly children in sub-Saharan Africa in 2020.This number is considered an achievement because it represents a 36% cut in malaria mortality between 2010 and 2020 due to the increasing number of stakeholders and resources available for malaria control.Most of these deaths are concentrated in the tropical and subtropical areas of the world, with Africa being the most affected area due to a combination of factors (see Fig. 1).
Africa is the most affected area with malaria due to many factors [17].First of all, Africa is the realm of a very efficient mosquito, Anopheles gambiae complex, which is the most efficient and specialized mosquito in malaria transmission in Africa.Second, the most predominant species of malaria in Africa is Plasmodium falciparum, which is the species of malaria that is most likely to cause severe malaria and death.Third, local weather conditions allow often for the transmission of malaria year-round.Finally, the socioeconomic instability of the region coupled with scarce resources makes malaria control a challenge.However, malaria transmission is increasing in areas of the world attributed to global warming and the migration of the Anopheles mosquito north [17].Local transmission of malaria is recorded in South America up to the southern part of the United States in North America.North America and regions of the United States including Florida and Texas are now reporting cases of locally transmitted malaria [18].

Epidemiology of Malaria in the US
There have been four cases of indigenous malaria transmission in the United States since 2000.The last time this happened was in 2003 in Palm Beach County, Florida.The collected Anopheles mosquitoes tested negative for Plasmodium, but both Anopheles quadrimaculatus and Anopheles crucians were seen across the area, raising concerns that they may be spreading the disease.Seven cases of malaria were discovered during this epidemic; testing confirmed that they were all caused by the same P. vivax strain.Travelers and immigrants from other countries, especially Mexican farmworkers, were identified as potential transmission sites [19].
Anopheles populations are already established in Florida, making the state vulnerable to malaria epidemics due to the state's high population density, growing international transportation hubs, favorable climatic conditions for parasite multiplication, and plenty of human hosts.Three young adults in Loudoun County, Virginia contracted P. vivax malaria in 2002 [20].Since the national malaria monitoring system began in 1957, this was the first time that mosquitoes positive for Plasmodium have been collected with human malaria cases in the United States.Patients' residences were more than 10 miles from the closest international airport, yet the Centers for Disease Control and Prevention (CDC) nonetheless concluded that local Anopheles mosquitoes likely acquired malaria from a nearby human [20], [21].
Malaria caused by P. vivax was reported twice more in the early 2000s, once in Suffolk County, New York, and once in Detroit, Michigan.Both Anopheles quadrimaculatus and Anopheles punctipennis collected locally lacked Plasmodium [22].The Centers for Disease Control and Prevention categorized these incidences as locally acquired since international airports are too distant from the anticipated infection locations and sick patients have no substantial travel history.There have been no confirmed cases of locally transmitted malaria in the United States since 2003, but the continued risk of transmission calls for increased local and state health department preparedness and response capabilities.

Locally Acquired Malaria the United States
In the years following the year 2000, the United States saw four occurrences of autochthonous malaria transmission.Each of these incidents provided new information on the vulnerability of the nation.Specifically, the most recent incident occurred in 2003 in Palm Beach County, Florida, in the United States.Plasmodium wasn't discovered in any of the Anopheles mosquitoes that were collected, although Anopheles quadrimaculatus and Anopheles crucians were prevalent throughout the area and were recognized as probable vectors.The seven P. vivax cases of 2003 were found to have been related to foreign visitors and immigrants, especially migrant laborers from Mexico, who were the probable source of infection [22].The MosquitoNET database, which is managed by the Centers for Disease Control and Prevention (CDC), has emerged as a useful resource in relation to the spread of Anopheles species.Data on mosquito surveillance and pesticide resistance were collected from a wide variety of beneficiaries of the Epidemiology and Laboratory Capacity (ELC) program around the country and are included in the database [23].These statistics, although not full, give some insights into the occurrence of distinct mosquito species in various areas of the country.The information was augmented by three counties in Florida that did not report to MosquitoNET, which led to an improved comprehension of the collection of Anopheles species.Remarkably, mosquitoes belonging to the genus Anopheles have been found in 32 states and one territory of the United States as shown in Table I [24] and Fig. 2. Some species of these mosquitoes are capable of transmitting malaria [25]- [28].It is important to note that twelve of these states are home to international airports that are listed among the top forty passenger gateways in the United States internationally [29].When focusing on the counties that encircle these international airports, it was found that both Anopheles quadrimaculatus and Anopheles punctipennis, which are both known to transmit malaria, were often observed.This is consistent with the distributional data collected throughout time for these species.
Fig. 2 shows that there have been reports of Anopheles mosquitoes in 32 states and one US territory, some of which are malaria-transmitting.Comparisons are challenging because not all areas provide data and that surveillance resources differ.Notably, 12 of the states hosting these mosquitoes have significant international airports, which may have an impact on the transmission of illness worldwide.
Between May 2023 and August 2023, the CDC [30] reported ten unusual cases of locally acquired malaria inside the United States, marking a first in the annals of epidemiology.This case study delves into the specifics of this event, primarily focusing on the seven reported incidents of malaria in Florida (P.vivax), one in Texas (P.vivax), one in Maryland (P.falciparum), and one in Arkansas (P.falciparum).These are the first confirmed cases of local malaria transmission in the United States in over two decades, therefore their epidemiological implications need careful analysis.About 2,000 cases of malaria are reported each year in the United States, most of which are attributable to infected travelers returning from malaria-sprawling areas.Already in 2018, 24 instances of imported malaria have been documented in Florida, highlighting the need for doctors and nurses to ask about patients' recent travels to see whether they may have been in a malaria-risk region [30].
Mosquito bites from local mosquitoes are the most likely explanation for locally acquired infections among travelers returning from malaria hotspots.These travelers then brought the malaria parasite back to the United States, where it was picked up by mosquitoes and spread to unsuspecting humans.It's important to note that the people who contracted malaria overseas may or may not have shown any symptoms, thus complicating attempts to identify and eliminate the disease [30].
In Florida, five instances were recorded over a month, and an unusual pattern formed in the form of regional clustering.The discovery of infected mosquitoes in the region is a major breakthrough.Despite the great distance between the two states, no strong epidemiological evidence has been found to connect the cases in Florida with those found in Texas.Studies of the malaria parasites' genomes have the potential to provide light on the causes and dynamics of these diseases.Such studies might help shed light on the regional distribution of the illness and inform future efforts to contain it [30].
Plasmodium vivax, the most common of the malaria parasites that infect people, was discovered in all of the individuals who had the disease recently.Public health initiatives to eradicate Plasmodium vivax have repeatedly failed.Although it may cause serious illness on rare occasions, it seldom results in death.The fact that Plasmodium vivax may lay latent in the liver of an infected person for years, re-infecting them even after intense therapy, is a particularly difficult obstacle to overcome.Finally, the appearance of locally transmitted malaria cases in Florida and Texas is a valuable case study that highlights the need to conduct thorough epidemiological research and adopt interdisciplinary techniques to better comprehend the dynamics of infectious diseases.As researchers learn more about this issue, they must work together to stop its spread and protect people's health in the United States.This case study may help healthcare providers, academics, and public health authorities better understand and respond to these rare but serious events [30].
The fight against malaria in the United States began in 1946 when the Centers for Disease Control and Prevention set out an important goal.Malaria, spread mostly by the Anopheles mosquito, was a serious hazard over much of the country's southern areas.The Centers for Disease Control and Prevention launched a full-scale program of pesticide spraying to combat disease spread.By 1951, thanks to their dogged efforts, malaria had been proclaimed eradicated in every country in the world [31].Recent events, however, have shown that the United States has not completely eliminated malaria, especially the reported locally transmitted cases since 2003 in Florida, Texas, Maryland, and Arkansas.Previously, the more than a thousand malaria cases reported in the US were attributed to people returning from areas where malaria is common.These locally transmitted malaria cases are attributed to the influence of climate change, which is increasing the spread of the anopheles mosquitos in the US  adding complexity to the issue of eliminating malaria in the United States.As discussed earlier, children under the age of five and pregnant women are more vulnerable to the illness despite the availability of excellent therapies [31].
A countrywide survey was conducted in 2017 in the US to assess the preparation of mosquito control agencies [15], [32]- [34].The purpose of the study was to gauge their skills for handling outbreaks of mosquito-borne viruses.The results of the study translate to the preparation for malaria outbreaks, even though the primary focus of the survey was on the capacity to deal with arboviruses.Only 8% of the mosquito control groups that were polled were regarded as "fully capable" in accordance with the criteria established by the CDC and the American Mosquito Control Association [35], [36].There was a lack of routine standardized mosquito monitoring in almost half of the organizations, which is essential for the preparation of malaria outbreaks.This was seen during the Zika epidemic that occurred in 2015-2016, which brought attention to the diminishing ability for entomological monitoring [37].

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Locally Acquired Malaria in the United States Some states did not have vector control programs that met all of the basic competencies, indicating that they were not well prepared for outbreaks of diseases that are transmitted by vectors.
It is necessary to take into consideration several risk variables to forecast future outbreaks of locally acquired malaria in the United States as shown in Table II [24] and Fig. 3.These include the inflow of people who are infected with malaria, the existence of malaria vectors, the weather conditions, and the level of readiness for an epidemic.In most cases, the states with the greatest malaria case burdens were also home to large international airports and reported the presence of Anopheles species that were competent to transmit the illness [24].It was shown that vulnerability to outbreaks was significantly related to lessthan-ideal preparation for vector-borne illness epidemics.
National Association of County and City Health Officials (NACCHO) ranking system is based on a scale from 1 to 5, with 1 denoting the highest level of preparedness, where all vector control programs in the state meet the core competencies, and 5 denoting the lowest level of preparedness, where none of the state's vector control programs meet the core competencies.

Climate Changes and the Rise of Malaria
Malaria is a fatal mosquito-borne illness that affects millions of people throughout the globe.Climatic change, defined as long-term alterations in climatic patterns owing to several reasons including human activities, may have Locally Acquired Malaria in the United States Naji a substantial influence on the incidence and spread of malaria.The spread of malaria is affected by weather conditions including temperature, precipitation, and humidity [10].Warmer temperatures may shorten the life cycle of mosquitoes, which in turn can spread malaria to more areas.The El Nino cycle may potentially have an impact on malaria transmission.Alterations in precipitation due to El Nino may have opposite effects on mosquito populations, encouraging breeding conditions in certain areas while drying out others.Malaria case counts may fluctuate as a result of this uncertainty.Malaria and climate change have been linked; however, this association is complicated by other variables such as poverty, lack of healthcare access, and pesticide resistance.Malaria may be made worse by climate change, but other factors, such as health and economic problems, might make people more susceptible to the illness.Malaria prevention efforts include using insecticide-treated nets in addition to other measures like monitoring and early diagnosis.Some nations have made significant strides in their elimination attempts, but climate change threatens to reintroduce the disease to places where it had been eradicated.As a result, in susceptible tropical regions and those with limited resources, monitoring and preparation are critical for reducing the effect of climate change on malaria transmission [10].
Climate change is likely to affect the prevalence of malaria.Malaria transmission seasons (LTSs) are expected to lengthen in highland regions due to climate change while shortening in tropical places.While the danger of malaria may decrease in western Africa, it is anticipated to rise in eastern Africa.The selection of malaria models, climate models, and emission scenarios are only a few of the many sources of uncertainty in these forecasts as depicted in Fig. 4 [11].Fig. 4 analyzes the different sensitivity of malaria models to climatic change, with some predicting a movement of the malaria epidemic belt northward into countries such as Europe and Russia.
It is worth noting that the environment in the African highlands is becoming more amenable to malaria transmission [38].However, these shifts, seen in Fig. 5, are highly dependent on the particular malaria and climate models used, which complicates estimating how global warming would affect malaria transmission.This leads to the necessity for continuous observation and action to manage the illness in a warming world, where transmission patterns may change [38].

CDC Recommendations
The Centers for Disease Control and Prevention (CDC) has issued a Health Alert Network (HAN) Advisory board to inform clinicians, public health authorities, and the public about three critical points.Firstly, there have been recent cases of locally acquired malaria caused by mostly Plasmodium vivax in Florida, Texas, Maryland, and Arkansas during 2023.Secondly, there's concern regarding a potential increase in imported malaria cases due to elevated international travel in the summer of 2023.Thirdly, there's an urgent need to prepare for rapid access to intravenous artesunate, the first-line treatment for severe malaria in the United States [30].
For clinicians, the CDC recommends considering malaria diagnosis in individuals with a fever of unknown origin, regardless of their travel history, especially if they Fig. 5. Future malaria distribution in light of possible climatic change [11].

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Locally Acquired Malaria in the United States have visited recent malaria-affected areas.They should also obtain a travel history from symptomatic patients and follow specific treatment guidelines depending on the malaria species and severity.Additionally, timely diagnosis and treatment are crucial as malaria can progress to severe disease without prompt intervention.Hospitals and laboratories are advised to have malaria diagnostic tests available and ensure qualified personnel can perform and interpret these tests.They should also have stockpiles of intravenous artesunate and other recommended antimalarials, ready for emergency procurement [30].
Public health officials should contact the CDC for assistance in cases of locally acquired malaria.They should also consider strategies for rapid identification, prevention, and control, including outreach and education to communities and collaboration with mosquito control programs.For the public, preventive measures against mosquito bites are emphasized, along with education about health risks when travelling to malaria-endemic areas and consultation with healthcare providers regarding malaria prophylaxis before international travel.If individuals develop symptoms like fever, chills, headache, body aches, and fatigue after travelling to malaria-affected areas, they should seek medical care and inform healthcare providers about their travel history [30].

Conclusion
The rise and reappearance of infectious illnesses underscore the urgent need to strengthen public health infrastructures that are currently failing and expose the vulnerabilities that exist within surveillance systems.The continuing COVID-19 pandemic has brought to light weaknesses in outbreak preparation and highlighted the critical need to enhance efforts at the local, state, and national levels to tackle newly developing and re-emerging health hazards all over the globe.The effect of the epidemic extends to include the possibility of a danger of malaria importation into the United States.It is anticipated that actions such as travel restrictions and lockdowns in nations that are prone to malaria may momentarily hinder international travel and, as a result, lessen the risk of malaria being imported.However, it is still unknown what long-term effects malaria will have on human movement and the likelihood of being exposed to disease-carrying mosquitoes.However, even though changes in outdoor activity and exposure have the potential to modify disease patterns, malaria continues to be a public health problem even in non-endemic locations like the United States.To guarantee the safety of people all over the world's health, it is essential to continue working to improve readiness for epidemics of malaria and other new illnesses.

Limitation
This study does have certain limitations, such as the absence of other data sources and a lack of statistical analysis; nonetheless, it does demonstrate the influence that malaria has on the United States even if these limitations exist.The danger of imported cases is not eliminated even when environmental variables and transmission dynamics are being disrupted by climate change.It is impossible to overstate the significance of changes in behavior, resistance to both insecticides and medications and the implications that these factors have for the future of malaria.

Fig. 4 .
Fig. 4. Comparison of the distribution of malaria in the wild (A and B) with that predicted by five different models (C-G) across three risk levels (white = no risk, blue = epidemic, and red = endemic) [10].

TABLE II :
[24]all Risk of Malaria by State[24]