Malaria Flashcards
Describe the cyclical nature of malaria symptoms and explain the biological basis for this pattern.
Malaria symptoms are cyclical, characterized by recurring fever spikes. This pattern is linked to the synchronous development of parasites within red blood cells. Parasites multiply inside red blood cells, causing them to burst and release more parasites into circulation. This cycle repeats, leading to the periodic fever spikes.
Explain the difference between eradication and elimination in the context of infectious diseases.
Eradication refers to the complete and permanent elimination of a disease worldwide, meaning no further cases occur. Elimination, on the other hand, refers to the removal of a disease from a specific geographic area, although the possibility of reintroduction remains. Smallpox is an example of an eradicated disease.
What were the two main methods used in the Global Malaria Eradication Programme, and what factors led to the suspension of the program?
The Global Malaria Eradication Programme primarily relied on spraying DDT to kill mosquitoes and distributing chloroquine as a medication. However, the program was suspended due to the emergence of both mosquito resistance to DDT and parasite resistance to chloroquine, along with escalating costs and funding shortages.
How did the emergence of chloroquine resistance affect the Global Malaria Eradication Programme?
The emergence of chloroquine resistance undermined the effectiveness of the Global Malaria Eradication Programme. The parasite’s ability to survive the drug rendered chloroquine less effective, leading to treatment failures and hindering the program’s goal of eliminating the disease.
Describe the unintended consequences of the widespread DDT spraying program in Borneo.
The DDT spraying program in Borneo had a cascade of unintended consequences. While it successfully killed mosquitoes and cockroaches, it also killed wasps that preyed on thatch-eating caterpillars. This led to the collapse of thatched roofs as caterpillar populations exploded. Furthermore, the bioaccumulation of DDT poisoned lizards, which in turn poisoned cats, leading to a surge in the rat population and outbreaks of typhus.
What are the primary ways in which bed nets help control malaria transmission?
Bed nets act as a physical barrier to prevent mosquitoes from biting people during sleep. Additionally, when treated with insecticides, they kill mosquitoes upon contact, reducing the overall mosquito population in the area. This combined approach limits both individual and community transmission of malaria.
Explain how the availability of data affects the implementation of new insecticide-treated bed nets.
The implementation of new insecticide-treated bed nets depends heavily on data availability. The WHO requires specific criteria to be met before deploying new nets, including evidence of insecticide resistance. A lack of sufficient data to demonstrate that an area meets these criteria can hinder the rollout of more effective nets, even in regions where resistance is known to exist.
What is the significance of The Global Fund in the fight against malaria?
The Global Fund plays a crucial role in the fight against malaria by providing a substantial amount of international financing for malaria programs. It contributes 62% of all international funding, making it a major driving force behind research, prevention, and treatment efforts in endemic countries.
Discuss the potential impact of climate change on malaria transmission.
Climate change has a complex and potentially significant impact on malaria transmission. While warmer temperatures and increased rainfall could create more favorable breeding grounds for mosquitoes, extreme weather events like floods can disrupt control measures and increase disease risk. Changes in temperature and humidity can also affect mosquito and parasite development, with uncertain consequences for transmission patterns. Further research is needed to understand the long-term impact of climate change on malaria incidence.
How has the geographical distribution of malaria changed over time?
Malaria was once prevalent in many parts of the world, including Europe and North America. Control efforts, including the use of DDT and chloroquine, led to a significant reduction in its distribution, primarily in developed countries. However, it remains endemic in many tropical and subtropical regions, particularly in sub-Saharan Africa.
What was the Global Malaria Eradication Programme, and why was it ultimately suspended?
Launched in 1955, the program aimed to eradicate malaria worldwide. It achieved success in some regions, but was suspended in 1969 due to several factors, including:
- The emergence of drug-resistant parasites
- The development of insecticide resistance in mosquitoes
- High costs and funding shortages
- Logistical difficulties, particularly in Africa, which was largely excluded from the program.
What are the main methods used to control malaria transmission?
- Vector control: This involves reducing mosquito populations through insecticide-treated bed nets (ITNs), indoor residual spraying (IRS), and larval source management.
- Treatment: Prompt and effective treatment of malaria cases using artemisinin-based combination therapies (ACTs) is essential to prevent complications and reduce transmission.
- Prevention: Preventive measures include chemoprevention for pregnant women and young children, and seasonal malaria chemoprevention (SMC) in areas with seasonal transmission.
- Surveillance: Tracking malaria cases, monitoring drug and insecticide resistance, and evaluating the effectiveness of control programs are crucial for guiding interventions
What was Operation Cat Drop, and why was it implemented?
Operation Cat Drop was an unusual initiative in Borneo in response to an unforeseen ecological consequence of using DDT to control malaria. The DDT killed wasps that preyed on thatch-eating caterpillars, leading to the collapse of thatched roofs. It also poisoned lizards, which were then eaten by cats, leading to a surge in the rat population and outbreaks of typhus. To address the rat problem, cats were parachuted into the affected areas
What is the significance of the development of malaria vaccines?
The development of malaria vaccines is a major breakthrough in the fight against the disease. While the currently available vaccines do not provide complete protection, they can significantly reduce the severity of malaria and prevent deaths, particularly in young children.
What are some of the key challenges to malaria control and elimination efforts?
- Drug and insecticide resistance: The emergence and spread of resistance to antimalarial drugs and insecticides threaten the effectiveness of current control tools.
- Climate change: Changes in temperature and rainfall patterns can affect mosquito breeding and survival, potentially altering malaria transmission dynamics.
- Zoonotic malaria: The emergence of zoonotic malaria, such as Plasmodium knowlesi, transmitted from animals to humans, poses new challenges to control efforts.
- Funding gaps: Sustained and adequate funding is crucial for maintaining and scaling up malaria control programs, and funding shortfalls can hinder progress.
- Data availability: Accurate and timely data on malaria cases, deaths, and drug and insecticide resistance is essential for effective surveillance, planning, and evaluation of control programs.
