the incidence rate of malaria may vary by what over the course of the year

by Rogelio Rosenbaum 7 min read

Globally, the malaria ASR decreased by an average 0.80% (95% confidence interval 0.58–1.02%) per year from 1990 to 2019; however, it slightly increased from 3195.32 per 100 000 in 2015 to 3247.02 per 100 000 in 2019. The incidence rate of children under 5 was higher than other age groups.

Full Answer

How does the number of deaths from malaria vary by age?

The number of deaths from malaria tends to decrease with age; with those over 70 years old accounting for around five percent. When age categories are combined, children under 14 years old account for more than two-thirds of mortality.

How many cases of malaria have been averted by interventions?

The study’s authors estimate that the three interventions averted 663 million cases of malaria in the 15 year period. Insecticide-treated bed nets were by far the most important intervention of the three, preventing 68% of the averted cases. Progress never happens by itself.

Where does malaria occur the most?

The malaria incidence is highest in the central part of Africa north and south of the equator. Humanity’s fight against malaria has a history of many thousand years. 2 For most of that time humanity was exposed to the disease without any defense.

Is the prevalence of malaria parasite infection increasing?

Different studies showed that the prevalence of malaria parasite infection has increased since 2015 [ 3, 4 ]. The causative agent of malaria is a small protozoon belonging to the group of Plasmodium species, and it consists of several subspecies. Some of the Plasmodium species cause disease in human [ 2, 5 ].

What is the incidence of malaria?

Malaria case incidence reduced from 81 in 2000 to 59 in 2015 and 56 in 2019, before increasing again to 59 in 2020. Globally, malaria deaths reduced steadily over the period 2000–2019, from 896 000 in 2000 to 562 000 in 2015 and to 558 000 in 2019. In 2020, malaria deaths increased by 12% compared with 2019.

What factors affect the distribution of malaria?

The three main climatic factors that directly affect malaria transmission are temperature, rainfall and relative humidity (the amount of moisture in the air).

What time of year is malaria most common?

Malaria transmission is seasonal in the Amhara region following seasonal patterns of climatic factors; the two main malaria transmission seasons occur in May–July following the end of the dry season and in September–December following the end of the wet season.

Does malaria increase with climate change?

An increase in temperature, rainfall, and humidity may cause a proliferation of the malaria-carrying mosquitoes at higher altitudes, resulting in an increase in malaria transmission in areas in which it was not reported earlier.

What increases the risk of malaria?

Known risk factors for malaria include low utilization of Insecticidal Treated bed Nets (ITNs), low utilization of Indoor Residual Spray (IRS), availability of multiple mosquito breeding sites or stagnant water sites near the home, and staying outdoors overnight [8,9,10,11].

What are the key determinants of malaria?

The age of the children, presence of anemia, education of the household head, household having electricity, access to television, residence type (rural or urban), and mosquito net use behavior for sleeping were found as significant determinants for malaria in children by both models, and the effects of these variables ...

Does malaria have a season?

Malaria is transmitted year-round.

Does malaria increase in rainy season?

The finding in this study corroborates our laboratory case records, which indicate that two weeks following the fall of the first rains usually registers increased cases of malaria infection.

Where is malaria most common?

Malaria occurs mostly in poor, tropical and subtropical areas of the world. Africa is the most affected due to a combination of factors: A very efficient mosquito (Anopheles gambiae complex) is responsible for high transmission.

How does climate and relief affect the prevalence of malaria?

Rainfall increases the breeding habitats for mosquitoes leading to increased population sizes and the rate of malaria transmission. The rate of development of the malaria parasite in female mosquitoes is very sensitive to ambient temperature.

What climate does malaria thrive in?

Malaria typically is found in warmer regions of the world — in tropical and subtropical countries. Higher temperatures allow the Anopheles mosquito to thrive.

How does rainfall contribute to malaria?

Areas of standing water created by heavy rainfall provide breeding grounds for malaria-carrying mosquitoes. Now, rainy seasons are getting more erratic, and increased flooding due to rising sea levels adds to the danger.

Which continent is most affected by malaria?

Africa is the world region that is most affected by malaria: In 2015, the African continent held 9 out of 10 malaria victims (click on ‘Expand’ to see this). But Africa is also the world region that has achieved most progress: from 2000 to 2015, African deaths from malaria were reduced from 764,000 to 395,000.

How many people died from malaria in 2015?

In these 15 years the global death toll has been cut in half: from 839,000 deaths in 2000 to 438,000 in 2015.

How did malaria affect the Roman Empire?

Malaria did not only leave its mark on our body, but in many ways also on our history. Malaria is presumed to have been the secret ally that helped the barbarians bring about the downfall of Rome. The examination of the teeth and bones of the Romans by archeologists has recently brought together more and more evidence that the mosquito-borne fever once thrived in the warm, marshy river valleys of the Tiber and the Po in the Roman empire. The disease enfeebled the mightiest army of the ancient world directly through epidemics and indirectly by reducing the productivity in the agricultural sector and hastened the fall of Rome. 5

Who discovered malaria?

Alphonse Laveran discovered already in 1880 that the Plasmodium parasite is the cause for malaria. 21 But all earlier attempts of developing a vaccines were unsuccessful. Malaria vaccines such as SPf66 were insufficiently effective and until recently none of the scientific efforts led to a licensed vaccine. 22

Was malaria eliminated in the 20th century?

Over the course of the 20 th century the disease was eliminated in many populous regions of the world, saving the lives of millions. What the map makes clear is that malaria is not a tropical disease, but a disease that was eliminated everywhere except for the tropics.

Where does malaria occur?

Malaria’s Impact. Malaria occurs mostly in poor tropical and subtropical areas of the world. In many of the countries affected by malaria, it is a leading cause of illness and death. In areas with high transmission, the most vulnerable groups are young children, who have not developed immunity to malaria yet, and pregnant women, ...

How does malaria affect the economy?

Social and Economic Toll. Malaria imposes substantial costs to both individuals and governments. Costs to individuals and their families include purchase of drugs for treating malaria at home; expenses for travel to, and treatment at, dispensaries and clinics; lost days of work; absence from school; expenses for preventive measures;

What are the most vulnerable people in the world?

The most vulnerable are persons with no or little immunity against the disease. In areas with high transmission (such as Africa south of the Sahara), the most vulnerable groups are: 1 Young children, who have not yet developed partial immunity to malaria 2 Pregnant women, whose immunity is decreased by pregnancy, especially during the first and second pregnancies 3 Travelers or migrants coming from areas with little or no malaria transmission, who lack immunity.

What is the most serious health problem in the world?

Malaria is one of the most severe public health problems worldwide. It is a leading cause of death and disease in many developing countries, where young children and pregnant women are the groups most affected. According to the World Health Organization’s World Malaria Report 2020#N#external icon

Is malaria a disease?

In other areas of the world, malaria is a less prominent cause of deaths, but can cause substantial disease and incapacitation, especially in some countries in South America and South Asia.

Where is malaria most common?

Malaria is the most common disease in Africa and some countries in Asia with the highest number of indigenous cases. The malaria mortality rate globally ranges from 0.3–2.2%, and in cases of severe forms of malaria in regions with tropical climate from 11–30% [2].

What is malaria caused by?

This article has been cited byother articles in PMC. Abstract. Malaria is a severe disease caused by parasites of the genus Plasmodium, which is transmitted to humans by a bite of an infected female mosquito of the species Anopheles.

Why is PCR used in malaria testing?

Additionally, PCR is useful for the monitoring of patients receiving antimalaria treatment [36,37]. Indirect methods are used to demonstrate antibodies to malaria-causing agents. Such methods are used in testing people who have been or might be at risk of malaria, such as blood donors and pregnant women.

How many people died from malaria in 2017?

Malaria affected an estimated 219 million people causing 435,000 deaths in 2017 globally. This burden of morbidity and mortality is a result of more than a century of global effort and research aimed at improving the prevention, diagnosis, and treatment of malaria [1].

Is malaria lower than ten years ago?

Globally, the burden of malaria is lower than ten years ago. However, in the last few years, there has been an increase in the number of malaria cases around the world. It is moving towards targets established by the WHO, but that progress has slowed down. Keywords: Anopheles, antimalarials, malaria, Plasmodium.

Where does Plasmodiumasexual develop?

The first phase of Plasmodiumasexual development occurs in the hepatocytes, and then in the erythrocytes.

Is there resistance to antimalarials?

Resistance has been reported to all antimalarial drugs. Therefore, research into finding and testing new antimalarials, as well as a potential vaccine, is still ongoing, mainly due to the sudden mass migration of humans (birds, parasite disease vector insects) from areas with a large and diverse infestation.

What is malaria in humans?

Malaria is a mosquito-borne infectious disease that has plagued humanity for centuries. Plasmodium parasites are the ones causing it. Then, female Anopheles mosquitoes spread the disease. Malaria statistics indicate that this disease is a major public health problem around the globe.

How many malaria deaths will there be in 2021?

Key Malaria Statistics for 2021. There were around 229 million cases of malaria across the world in 2019. Six countries account for half of all malaria deaths in the world. Since 2000, around 1.5 billion malaria cases and 7.6 million deaths have been prevented.

How many people died from malaria in 2016?

In 2016, there were around 3 million new malaria cases, resulting in roughly 4,782 deaths. That is a considerably lower number compared to the record-breaking 10,412 deaths registered in 2000. As is the case with other African countries, in Ethiopia, children under the age of five are the most affected.

How much does malaria cost?

Malaria costs around $12 billion per year in direct expenses. (CDC) These costs are not centered on prevention but rather on the disease, treatment, and premature deaths. The actual cost of lost economic growth (and, of course, in human lives) is substantial and difficult to calculate.

What is the cause of malaria in Africa?

One of the causes of malaria in Africa is local weather conditions combined with social and economic instability.

Which country has the highest number of malaria cases and deaths in 2018?

As more children get to sleep under an ITN, there is hope that this disease will no longer be the leading cause of death among kids in the sub-Saharan region. 22. Nigeria had the highest number of malaria cases and deaths in 2018.

How many days of school do children miss in Nigeria?

A study in Kenya indicates that this disease results in 4 to 10 million lost days of school. When it comes to malaria in Nigeria, statistics show that children miss an average of three days of school per episode annually. That, in turn, accounts for 2% to 8% of all episodes of school absenteeism.

What is period prevalence?

It is the proportion of persons with a particular disease or attribute at any time during the interval.

How does incidence rate work?

An incidence rate describes how quickly disease occurs in a population. It is based on person-time, so it has some advantages over an incidence proportion. Because person-time is calculated for each subject, it can accommodate persons coming into and leaving the study. As noted in the previous example, the denominator accounts for study participants who are lost to follow-up or who die during the study period. In addition, it allows enrollees to enter the study at different times. In the NHANES follow-up study, some participants were enrolled in 1971, others in 1972, 1973, 1974, and 1975.

What is the numerator of the incidence rate?

Similar to the incidence proportion, the numerator of the incidence rate is the number of new cases identified during the period of observation. However, the denominator differs. The denominator is the sum of the time each person was observed, totaled for all persons.

What is the difference between prevalence and incidence?

Prevalence and incidence are frequently confused. Prevalence refers to proportion of persons who have a condition at or during a particular time period, whereas incidence refers to the proportion or rate of persons who develop a condition during a particular time period.

How is the incidence rate calculated?

A person-time rate is generally calculated from a long-term cohort follow-up study, wherein enrollees are followed over time and the occurrence of new cases of disease is documented. Typically, each person is observed from an established starting time until one of four “end points” is reached: onset of disease, death, migration out of the study (“lost to follow-up”), or the end of the study. Similar to the incidence proportion, the numerator of the incidence rate is the number of new cases identified during the period of observation. However, the denominator differs. The denominator is the sum of the time each person was observed, totaled for all persons. This denominator represents the total time the population was at risk of and being watched for disease. Thus, the incidence rate is the ratio of the number of cases to the total time the population is at risk of disease.

What is incidence proportion?

Incidence proportion is a measure of the risk of disease or the probability of developing the disease during the specified period. As a measure of incidence, it includes only new cases of disease in the numerator. The denominator is the number of persons in the population at the start of the observation period.

What does low prevalence mean?

Conversely, low prevalence might indicate low incidence, a rapidly fatal process, or rapid recovery.

Prevention

  • Over the last 2 decades, expanded access to WHO-recommended malaria prevention tools and strategies – including effective vector control and the use of preventive antimalarial drugs – has had a major impact in reducing the global burden of this disease.
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Case Management

  • Early diagnosis and treatment of malaria reduces disease, prevents deaths and contributes to reducing transmission. WHO recommends that all suspected cases of malaria be confirmed using parasite-based diagnostic testing(through either microscopy or a rapid diagnostic test). Diagnostic testing enables health providers to swiftly distinguish between malarial and non-mal…
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Elimination

  • Malaria elimination is defined as the interruption of local transmission of a specified malaria parasite species in a defined geographical area as a result of deliberate activities. Continued measures to prevent re-establishment of transmission are required. In 2020, 26 countries reported fewer than 100 indigenous cases of the disease, up from 6 countries in 2000. Countries that hav…
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Surveillance

  • Malaria surveillance is the continuous and systematic collection, analysis and interpretation of malaria-related data, and the use of that data in the planning, implementation and evaluation of public health practice. Improved surveillance of malaria cases and deaths helps ministries of health determine which areas or population groups are most affected and enables countries to …
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Who Response

  • The WHO Global technical strategy for malaria 2016–2030, updated in 2021, provides a technical framework for all malaria-endemic countries. It is intended to guide and support regional and country programmes as they work towards malaria control and elimination. The strategy sets ambitious but achievable global targets, including: 1. reducing malaria case incidence by at leas…
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