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Biology 1100: Pathogens

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Biology 1100: Pathogens

Introduction

Pathogens are the organisms causing diseases and include bacteria, viruses, protozoa,

fungi, and worms. Notably, pathogens are found in different body compartments where various

host defense mechanisms combat them. The majority of pathogens cannot be completely

eradicated through an immune response. The human body is vulnerable to different infections

caused by pathogens, which initially make contact with the host and later develop a focus on

infection to cause diseases. To understand more about pathogens, the paper will analyze the

history, spread, cure, and management of measles and malaria.

Measles

History

During the Middle Ages, measles famously known as "morbilli," meaning little disease,

and was reported in South Asia, China, and Europe. During the Spanish invasion, measles and

smallpox had the highest mortality rates among Amerindians, particularly during the Mexican

invasion in 1521. Additionally, in 1529, measles epidemics were reported in Cuba, leading to the

death of a third of the native population who had previously survived smallpox. Moreover, a

measles epidemic was reported in Honduras in 1531 and affected 50% of the population (Berche,

2022). Pacific Island and North Atlantic were the only regions spared from measles at the

beginning of the nineteenth century. The disease epidemiology was studied by Peter Panum

(Danish physician) in 1846 during the Faroe Islands epidemic. John Enders and Thomas Peebles

identified the virus in 1954(Berche, 2022). Ender's team also developed the attenuated vaccine in

1958 after several passages within cell cultures. The United States licensed the vaccine in 1963,
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and the World Health Organization (WHO) used it on a large scale globally. The justifiable and

effective vaccine has reduced measles cases and helped to save lives. Today, measles is still a

major health issue causing nearly 100,000 deaths every year globally (Berche, 2022). Africa,

Asia, and South America are the most affected continents.

Spread

Measles is a infectious disease which is spread by aerosols through human-to-human

interaction. The disease is characterized by seasonal epidemics, especially during winter, because

of risk factors like crowded places and schools opening (Misin et al.2020). Measles is

transmitted through respiratory droplets in shorter distances and also by small particles of

aerosols which remain suspended throughout the air. The infected droplets of the measles virus

remain suspended in the air for a certain duration, and unaffected persons can easily inhale it.

According to WHO (2023), measles is transmitted by contact with throat secretions and infected

nasal (sneezing or coughing) and also by breathing the same air as a person with measles. In this

case, being close to an infected individual who sneezes or coughs increases the chances of

spreading. Additionally, contaminated objects and surfaces can also transmit the measles virus.

For example, if an individual touch objects or surfaces contaminated with the virus and touch

their nose, mouth, and eyes, they become infected.

Cure

There is no specific treatment for measles; however, WHO recommends daily

administration of vitamin A for two days among malnourished children. It helps to prevent

blindness and eye damage. Notably, supplements in vitamin A minimize deaths associated with

measles. Vitamin A needs to be administered to children with immunosuppression and those

immigrating from regions with high mortality rates (Solomon, 2019). Additionally, management

and supportive care are needed to alleviate signs and symptoms and prevent further

complications. Healthcare providers use medications like ibuprofen and acetaminophen to

manage discomfort and fever. Aspirin needs to be avoided, especially among children, because

of the risks associated with Reyes syndrome. Supportive therapy helps to prevent dehydration,

treat nutritional deficiencies, and detect bacterial infections like otitis media and pneumonia.

Management

Vaccination is the most effective way of controlling and managing measles worldwide.

This means that all children need to be vaccinated against measles (WHO, 2023). Children

should at least receive two doses of vaccine to remain immune. In this case, the first dose should

be provided at nine months of age, especially in countries where the disease is common, and

twelve to fifteen in other countries. Massive immunization campaigns and routine vaccination in

regions where high reported cases are critical in reducing measles deaths. The vaccine is used

during emergencies to prevent outbreaks from spreading rapidly. The vaccine is given after

seventy-two hours of measles exposure attenuates or prevents the disease in vulnerable persons

(Solomon, 2019). Additionally, infants, pregnant women, and immunocompromised persons

should be administered globulin to prevent other severe diseases.

Malaria

History

Malaria has troubled humans for several years. Francisco Torti, an Italian physician, was

the first person to coin the term malaria as bad air in 1718. Louis Alphonse, a French surgeon in

1880, reported parasites in malaria patient blood. He examined samples of one hundred and
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ninety-two patients and found pigments containing crescents of one hundred and forty-eight

patients (Rawal, 2020). Italian physiologist Camilio Golgi described the two forms of diseases:

quartan and tertian fever. He also indicated that malaria fever was a result of the release and

rupture of merozoites in the blood system. Giovanni Battista, in 1890, was the first to coin

malaria parasites, Plasmodium malaria and Plasmodium vivax, which infect humans (Rawal,

2020). Ronald Ross, in 1897, discovered that mosquitoes cause malaria and also described

malaria life cycle. While working in India, Ross discovered that the malaria parasites were

usually transmitted by infected Anopheles mosquitoes. Notably, the discovery confirmed the

hypothesis by Manson about mosquito transmission. The efforts to control malaria in the

twentieth century concentrated on minimizing mosquito breeding sites.

Spread

An interaction between mosquitoes, humans, and pathogens causes malaria. Malaria is

transmitted to persons through bites of disease-ridden female anopheles mosquitoes.

Contaminated needles and blood transfusion also transmit malaria. Notably, the initial symptom

is mild, similar to febrile illnesses, and challenging to recognize as malaria (Savi, 2022).

Individuals with inadequate and untreated malaria are likely to spread infections to mosquitoes

biting them. The infected mosquitoes spread the disease by infecting and biting healthy

individuals. There is no direct transmission from one individual to another. Transmission

intensity of malaria differs across the host populations since vector attraction to the host usually

varies. Notably, the variation is stimulated by differences in human bodies and reactions of

mosquito bites (Savi, 2022). For example, infected hosts are more attractive to other mosquitoes

as compared to non-infected ones. Similarly, female mosquitoes desire the scent of kid to that of

adult. Several factors contribute to the spread of malaria to the general population, like
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environmental factors, including stagnant water serving as breeding areas for anopheles

mosquitoes. Temperature and climate also play a critical role in mosquito breeding and malaria

transmission. For example, a warm climate increases malaria transmission and mosquito

activities.

Cure

Before the treatment of malaria begins, it is important to establish a diagnosis. During

oral treatment, physicians prefer artemether-lumefantrine since it is fast in action. Other oral

options for treating malaria include mefloquine, quinine, and atovaquone–proguanil, and

tetracyclines. Notably, these antibiotics are not effective when treating severe malaria as they are

slow–acting. Healthcare providers also use Artemisinin-based combination therapies (ACTs),

which is a combination of two or even more antibiotics that work best against malaria parasites

in diverse ways. It is the most preferred form of treatment, especially in chloroquine malaria-

resistant. According to Talapko et al. (2019), ACT therapies are resistant to sulfadoxine-

pyrimethamine, chloroquine, and amodiaquine. Additionally, physicians use atovaquone-

proguanil to treat and prevent malaria. The antibiotics are most prescribed to travelers visiting

malaria–endemic areas since it is effective against Plasmodium vivax and Plasmodium

falciparum.

Management

One of the effective strategies to prevent the spread of malaria is vector control. This

method includes measures directed against vector diseases to limit the ability to transmit diseases

through the protection of areas identified as receptive for transmission. The vector control

measures should match the local setting to acquire optimal effectiveness (Tizifa et al.2018). A
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good example of a vector control measure is indoor residual spraying, which is a global

eradication campaign that helps to control epidemics. Another preventive measure is the use of

bed nets to prevent biting by Anopheles mosquitoes. The insecticide-treated bed nets (ITNs) are

usually treated with insecticides that kill and repel mosquitoes and provide physical barriers to

preventing mosquito bites. Malaria vaccination introduced by WHO can also help prevent the

spread of malaria, especially in areas where Plasmodium falciparum is prevalent. This vaccine

helps children living in malaria–endemic regions by providing partial protection against

parasites. Lastly, clearing stagnant water and effective disposal of trash help to reduce mosquito

populations.

Conclusion

The paper has examined the historical background, transmission patterns, treatment, and

preventive strategies of measles and malaria to understand these pathogens better. Measles is a

contagious disease spread by aerosols through human-to-human interaction. WHO recommends

daily administration of vitamin A for two days among malnourished children with measles.

Vaccination is the most effective way of controlling and managing measles worldwide. On the

other hand, malaria is transmitted to persons through bites of disease-ridden female anopheles

mosquitoes. Artemisinin-based combination therapies (ACTs), which are a combination of two

or even more antibiotics, work best against malaria parasites in diverse ways.
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References

Berche, P. (2022). History of measles. La Presse Médicale, 51(3), 104149.

https://doi.org/10.1016/j.lpm.2022.104149

Misin, A., Antonello, R. M., Di Bella, S., Campisciano, G., Zanotta, N., Giacobbe, D. R., Comar,

M., & Luzzati, R. (2020). Measles: An Overview of a Re-Emerging Disease in Children

and Immunocompromised Patients. Microorganisms, 8(2), 276.

https://doi.org/10.3390/microorganisms8020276

Rawal, D. (2020). An overview of natural history of the human malaria. Int J Mosq Res, 7(2), 8-

10.

Savi, M. K. (2022). An Overview of Malaria Transmission Mechanisms, Control, and

Modeling. Medical Sciences, 11(1), 3. https://doi.org/10.3390/medsci11010003

Solomon, C. G. (2019). Peter M. Strebel, MB, Ch. B., MPH, and Walter A. Orenstein,

MD. Vaccine, 500, 1200.

Talapko, J., Škrlec, I., Alebić, T., Jukić, M., & Včev, A. (2019). Malaria: the past and the

present. Microorganisms, 7(6), 179. https://doi.org/10.3390/microorganisms7060179

Tizifa, T. A., Kabaghe, A. N., McCann, R. S., van den Berg, H., Van Vugt, M., & Phiri, K. S.

(2018). Prevention efforts for malaria. Current tropical medicine reports, 5, 41-50.

https://doi.org/10.1007/s40475-018-0133-y

WHO. (2023, August 9). Measles. World Health Organization

(WHO). https://www.who.int/newsroom/factsheets/detail/measles