Nutri Sci Lec 21 Malaria

Communicable disease

Infectious or transmissible from human to human, animal to human or human to animal

Difference between communicable and non communicable diseases

Communicable diseases are caused by microorganisms

Communicable diseases are among the __ causes of death in low-income and marginalized populations

Leading

The burden of communicable disease in terms of DALYs has a disproportional effect in __

Sub Saharan Africa

Burden of communicable disease has been __ globally, but they still are major problems

decreasing

Communicable diseases are some of the __ causes of death for children under 5

main

What are the three main diseases responsible for childhood death under 5?

Pneumonia, diarrhea and malaria

___% of deaths due to HIV, TB and malaria occur in low income countries in Africa and South Asia

99%

Epidemiology def

The study of distribution and determinants of health-related events or states in specified populations and the application of this study to control health problems

What is the epidemiological triad?

A simple model for infectious disease comparisons: Host, etiologic agent, environment

Disease results from the interaction between the agent and the susceptible host in an environment that supports transmission of the agent from a source to that host

Incidence def

Number of new cases in a given period of time

Prevalence def

Number of total cases at a given time

Host def

A person or animal that affords subsistence to a lodgment to an infectious agent under natural conditions

Examples of determinants of disease for the host

• Demographic characteristics: sex and age

• Biological characteristics: immune status, genetic traits

• Socioeconomic characteristics: Poverty, education and geography

Modes of transmission for infectious agents

• Contact

• Sex or blood-borne

• Inhalation or air-borne

• Food-borne

• Water-borne

• Vector-borne

__% of malaria deaths in Africa occur in children <5

80%

Socio economic impacts relating to malaria transmission

• Cost to individuals and families: including drugs for treatment, lost days of work and school

• Costs to governments: sustaining health systems, costs of interventions, loss of income from lost days of work

• Direct costs have been estimated to be at least $12 billion per annum

Africa comprises __% of global malaria cases

94%

What is the vector for malaria? What is the parasite?

• Vector: anapholes gambiae mosquito

• Parasite: Plasmodium falciparum

Populations at risk of death from malaria

• Infants, children and pregnant women

• People traveling through endemic regions

• People with HIV/AIDS

• Anyone with low immunity

Is malaria present in the US?

Kind of. Only two locally acquired cases in the US documented. 2,000-2,500 malaria cases occur in the US but due to traveling

Describe plasmodium falciparum

• Crescent shaped gametocyte

• Eukaryotic, making it harder to treat

Anopheles gambiae breeds in __ waters

Stagnant

Only __ anopheles gambiae mosquitoes bite

female

Anopheles gambiae are both __phagic and __philic

Endophagic (feed indoors) and endophilic (rest and live indoors inside human dwellings)

Describe the stages of malaria

Classical acute phase that lasts 6-10 hrs with episodes of…

• Cold stage

• Hot stage (hot fever)

• Sweating stage

The symptoms of malaria correlate with the __ cycle

parasite

If malaria is left untreated, it can advance to…

renal failure, cerebral malaria and death

Cyclic symptoms of malaria result from…

Synchronous release of parasites from blood cells and subsequent rounds of replication and release/reinvasion

What are the 3 ways that malaria kills children?

• Infection in pregnancy leading LBW and preterm delivery

• Acute illness which can lead to cerebral malaria, coma and seizures

• Chronic repeated infection which can lead to acute anemia

What are some current tools for malaria prevention and control?

• Drug therapy prevention and treatment

• Anti-mosquito bed nets (insecticide treated nets)

• Anti mosquito insecticide residual sprays

• Antimalarial vaccines

Primary treatment for people infected with malaria

Artemisinin-based combination therapy

Primary drug treatments for travelers

• Atovaquone; doxycycline; mefloquine

• Intermittent treatment with sulfadoxine-pyrimethamine

__% of people in Sub-saharan Africa use bed-nets

43%

What’s the cost of a bed net?

$2-$5?

Why might people be lacking bed nets even if they’re so helpful?

They can’t afford them or they have no electricity (the bed nets are very warm and if they have no AC it can be overbearing)

When did two malaria vaccines come out and what are their efficiencies?

2021 and 2023, pretty high efficiency (up to 75% reduction in cases), pretty cost effective

Large rollout for malaria vaccines began in ___

2024

Malaria mortality rate has decreased by __% from 2000-2020

49%

As of 2024, __ countries and one territory have been certified as malaria-free by the WHO

44

What are threats to malaria elimination?

• Vector insecticide resistance

• Parasite gene deletion mutations

• Parasite drug resistance

What are some vector control tools in development

• New insecticides, formulations or methods of application

• New attractants and repellents

• New bioactive agents (like fungi)

• New mosquito life-cycle targets

• Genetically modified mosquitoes

• Endectocides: antiparasitic drugs that act as a systemic poison to the mosquito when it blood feeds