THE SCIENCE OF MALARIA: BIOLOGY, EPIDEMIOLOGY & PUBLIC HEALTH

Dr. Rebecca Duerst, Program Director for Health Care

ELCA Synod Malaria Summit20-22 March 2014

Outline

True or False on malaria biology, epidemiology, and public health

Scientific advances in malaria work Time for Q&A

True or False?Biology, Question 1 Q: Malaria is caused

by mosquitos A: False Explanation: Malaria is

caused by parasites in the genus Plasmodium; it is transmitted by female Anopheles mosquitoes

True or False?Biology, Question 2 Q: There are 4 species of Plasmodia known to cause

malaria in humans A: False The 4 main species causing

human malaria are: Plasmodium falciparum Plasmodium ovale Plasmodium vivax Plasmodium malariae

A 5th species, Plasmodium knowlesi (“nolls-eye”), is now recognized as an important cause of human disease in Southeast Asia; it is responsible for up to 75% of malaria infections in some areas

True or False?Biology, Question 3 Q: The life cycle of Plasmodium parasites is

complex A: True http://www.cdc.gov/malaria/about/biology

a Female Anopheles mosquitoes require a blood meal for egg development. Infected females inject the sporozoite form into a human host. b Sporozoites are carried in the bloodstream to liver cells, where they proliferate asexually and release merozoites. c Merozoites invade red blood cells and reproduce asexually; disease clinically manifests as fever & chills. d Then male and female gametocytes are produced and transmitted back to a mosquito, where they fuse to form oocysts that divide into sporozoites. These migrate to the salivary glands.

True or False?Epidemiology, Question 1 Q: Epidemiology is the branch of

medicine dealing with physiology and pathology of the skin

A: False Epidemiology is the study of distribution

and determinants of health-related states / events (including disease), and the application of this study to control diseases and other health problems (WHO)

True or False?Epidemiology, Question 2 Q: Africa carries the majority of the world’s burden of

malaria A: True

True or False?Epidemiology, Question 3 Q: Malaria has no relationship to poverty, HIV&AIDS,

climate change, etc. A: False www.gapminder.org

True or False?Public Health, Question 1 Q: Despite much progress, malaria is still a major

public health concern globally A: True 2012 estimated malaria cases:

207 million 80% occur in sub-Saharan Africa

2012 estimated malaria deaths: 627,000 90% occur in sub-Saharan Africa, 77% in children under

5 years of age An estimated 3.3 million deaths were averted

between 2000-2012

True or False?Public Health, Question 2 Q: Focusing efforts only on net

distribution is the best strategy for malaria prevention

A: False WHO promotes integrated approach

(“integrated vector management”) including LLINs, IRS, & environmental management, along with education, prompt diagnosis and effective treatment, surveillance, etc.

http://www.npr.org/blogs/health/2014/01/03/257627285/why-ending-malaria-may-be-more-about-backhoes-than-bed-nets

True or False?Public Health, Question 3 Q: Artemisinin (key ingredient in ACT) is

still 100% effective throughout the world A: False Parasite resistance to artemisinins has

been detected in 4 countries in Southeast Asia Cambodia, Myanmar, Thailand and Viet Nam

In Cambodia, resistance has been found to both components of ACT Special provisions have been made for DOT

with a non-artemisinin-based combination

True or False?Final Question Q: Because malaria is such a focus of global health efforts,

extensive, accurate data is available A: False There is more uncertainty about malaria than any other

disease Malaria surveillance systems detect <10% of estimated

cases - Richard Cibulskis, WHO Global Malaria Programme, 2011

SCIENTIFIC ADVANCES IN MALARIA RESEARCH

New ideas & technological innovations

Testing & Diagnosis:Detection methods Phone camera microscopes

“CellScope” (relatively expensive) 1mm glass ball, cardboard, tape

“Origami” microscope (6 March 2014) http://youtu.be/pBjIYB5Yk2I

Testing & Diagnosis:Detection methods “Matibabu” blood scanner (Swahili for “medical

center”) http://

news.discovery.com/tech/videos/phone-app-diagnoses-malaria-video.htm

Brian Gitta, Makerere University, Uganda pitches his idea that uses cell phones and light – not needles and blood samples to test for malaria (USAID).

Malaria vaccinePrime candidates PfSPZ (Sanaria) – August, 2013

6 volunteers received 5 IV doses each, over 20 weeks 100% protection, but impractical conditions

RTS,S (GSK) – October, 2013 (18 mo. follow-up) Protection lasted over 18 months, though waned

slightly Reduced malaria cases in children by nearly half (46%) Adding a booster dose at 18 months is now being studied Policy recommendation from WHO is possible in 2015

http://www.npr.org/blogs/health/2013/10/08/230356317/first-malaria-vaccine-moves-a-step-closer-to-approval

DrugsNew targets? AP2-G protein – February, 2014

Master switch that triggers activation of genes that initiate the development of gametocytes (only form infectious to mosquitos)

CAX protein – April, 2013 Transporter that controls calcium

level inside cells (Artemisinin interferes with the other Ca+2 transporter)

Parasites die before developing inside mosquito when CAX does not function

MosquitosAltering the vector GM mosquitos (?)

Mosquito blood has proteins that punch holes through the parasite’s membrane

Engineer mosquitos that produce in higher amounts

Wolbachia-infected mosquitos Bacteria naturally occuring in

other species of mosquitos Confers resistance to malaria

(and dengue virus)

Thank you!