The risk of malaria worldwide: prospects for control and elimination

Bob SnowKEMRI-University of Oxford

collaboration, Nairobi, Kenya

www.map.ox.ac.uk

Evangelism and global malaria eradication - 2008

Context

Risks and types of disease different in different parts of the world

Suites of control strategies need to be tied to the basic scientific understanding of risk

The future of malaria control worldwide must be driven by a map – the last one developed almost 50 years ago

Global limits of P. falciparum malaria – 87 countries in 2007

Guerra et al. (2008) PLoS Medicine

Iterated spatial Pf limits based on – Med Intelligence mapping and biology of parasite with remotely sensed satellite data on Temperature and Aridity

Guerra et al. (2008) PLoS Medicine

Interpolated global stable endemic surface of P. falciparum parasite prevalence to 2007

Hay et al. (2009) PLoS Medicine

0.9 Billion people at unstable risk < 1 case per 10,000 people each year

1.4 Billion people at stable risk

67% of world population exposed to any risk of P. falciparum live in Central and South Asia and Pacific

73% of P. falciparum risk world live in areas of unstable or low endemic risk

Only 14% of Pf world live in areas of high transmission – 98% in Africa

In 2007…..

Americas

91 million people at risk of Pf

50 Million in Unstable areas

41 Million in areas where PfPR < 5%

South, Central and Eastern Asia

1.6 Billion people at Pf risk911 million at risk of unstable transmission (57%)603 million at risks of stable transmission with PfPR <5% (38%)80 million people at risk of transmission > 5% (5%)

Africa679 million people at risk of Pf – ¾ Africans171 million (25%) in stable PfPR 5-39%377 million (56%) in Stable PfPR 40%+

428 Million clinical events in all ages

0.98 Million deaths directly due to PF among children aged 0-4 years

Malaria-specific mortality in African children aged 0-4 years per 1000 children p.a. from 31 community-based

surveillance studies between 1985-2004

What are we shooting for in Africa?

What can be done to reduce the public health burden of P. falciparum?

Just two simple interventions that cost a few dollars per person each year

Effective and prompt treatment with drugs that work

Protection from infectious bites through the use of a net treated with insecticide or IRS

Speed of international public health policy change

2003

2004

2007

Percentage of Kenyan Health facilities without Paed doses of AL on day of survey?

3/5 health facilities don’t have drugs to treat malaria effectively in young children……….

Of children living in stable endemic areas of Africa

c. 2000 4% under an ITN

c. 2007 18% under an ITN

Intervention Coverage - ITNs

90 million children do not sleep under an ITN in 2007

Most within only 7 countries

25% of all unprotected children are Nigerian

Noor et al., Lancet 2009, 373: 58-67

2004 Social Marketing & Commercial Sector approaches – 33 Million USD

2005 Above + heavily subsidized – 54 Million USD

2006 Above + FREE – 17 Million USDNoor et al., PLoS Med (2007)

The Kenyan Example

Financing Stable populations at risk per capita national and international funding unmet financial need in 2007

20 countries < 1$ per person

Only three countries > 4$ per person

Djibouti

ST&P Equatorial Guinea

Snow et al., PLoS Medicine 2008, 5: e142

We must get the plan for Africa right

We can make a huge public health difference in our life-times without elimination – a legacy we’d all be proud of

We can predict this impact and we can measure it

The way forward?

There are some areas of the world where regional or small scale elimination is feasible but these areas must ensure political and financial sustained commitment themselves

World Vision launches bold initiative for worldwide elimination of mosquitoes15 Oct 2008 - Source: ASSIST News Service

Richard Stern pointed out that now it's time for the rest of the world to benefit from the U.S experience and that by God's mercy and in partnership with other humanitarian organisations and individuals, World Vision is determined to end malaria in the entire world.

Tanzania still expecting to eradicate malaria by 201520 Oct 2008 By Christopher Magola, Dar es Salaam

Rwanda - Anti-mosquito spraying19 Oct 2008 By Frank Kagabo – The New Times Rwanda Late last year, the country embarked on a spirited anti-mosquito spray in homes with a view of eradicating malaria, from the country

How is this interpreted internationally and regionally?

Malaria to be eradicated in Nigeria by 201514 Aug 2008 by AbdulAzeez Sani Lagos Times Minister of State for Health, Arc. Gabriel Aduku, has disclosed that the federal government has set 2015 for the total eradication of malaria in the country