Malarial ecology: A global perspective

Dutta, Hiran M.; Dutt, Ashok Κ.

doi:10.1016/0037-7856(78)90001-x

Cited by 9 publications

(8 citation statements)

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“…falciparum endemicity was published in 1968 [5]. In common with all previous maps of the global distribution of malaria [6–10], and to a large extent those that followed [11–16], the map (i) suffered from an incomplete description of the input data used; (ii) defined contours of “risk” using subjective and poorly explained expert-opinion rules; and (iii) provided no quantification of the uncertainty around predictions. Here we describe the generation of a new global map of malaria endemicity that overcomes these major deficiencies.…”

Section: Introductionmentioning

confidence: 99%

A World Malaria Map: Plasmodium falciparum Endemicity in 2007

et al. 2009

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BackgroundEfficient allocation of resources to intervene against malaria requires a detailed understanding of the contemporary spatial distribution of malaria risk. It is exactly 40 y since the last global map of malaria endemicity was published. This paper describes the generation of a new world map of Plasmodium falciparum malaria endemicity for the year 2007.Methods and FindingsA total of 8,938 P. falciparum parasite rate (PfPR) surveys were identified using a variety of exhaustive search strategies. Of these, 7,953 passed strict data fidelity tests for inclusion into a global database of PfPR data, age-standardized to 2–10 y for endemicity mapping. A model-based geostatistical procedure was used to create a continuous surface of malaria endemicity within previously defined stable spatial limits of P. falciparum transmission. These procedures were implemented within a Bayesian statistical framework so that the uncertainty of these predictions could be evaluated robustly. The uncertainty was expressed as the probability of predicting correctly one of three endemicity classes; previously stratified to be an informative guide for malaria control. Population at risk estimates, adjusted for the transmission modifying effects of urbanization in Africa, were then derived with reference to human population surfaces in 2007. Of the 1.38 billion people at risk of stable P. falciparum malaria, 0.69 billion were found in Central and South East Asia (CSE Asia), 0.66 billion in Africa, Yemen, and Saudi Arabia (Africa+), and 0.04 billion in the Americas. All those exposed to stable risk in the Americas were in the lowest endemicity class (PfPR2−10 ≤ 5%). The vast majority (88%) of those living under stable risk in CSE Asia were also in this low endemicity class; a small remainder (11%) were in the intermediate endemicity class (PfPR2−10 > 5 to < 40%); and the remaining fraction (1%) in high endemicity (PfPR2−10 ≥ 40%) areas. High endemicity was widespread in the Africa+ region, where 0.35 billion people are at this level of risk. Most of the rest live at intermediate risk (0.20 billion), with a smaller number (0.11 billion) at low stable risk.ConclusionsHigh levels of P. falciparum malaria endemicity are common in Africa. Uniformly low endemic levels are found in the Americas. Low endemicity is also widespread in CSE Asia, but pockets of intermediate and very rarely high transmission remain. There are therefore significant opportunities for malaria control in Africa and for malaria elimination elsewhere. This 2007 global P. falciparum malaria endemicity map is the first of a series with which it will be possible to monitor and evaluate the progress of this intervention process.

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Section: Introductionmentioning

confidence: 99%

A World Malaria Map: Plasmodium falciparum Endemicity in 2007

et al. 2009

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“…Both altitude (a proxy for low ambient temperature) and deserts have been used to define the absence of malaria transmission in most previous iterations of global malaria maps (Boyd, 1930; Dutta and Dutt, 1978). Temperature plays a key role in determining the transmission of human malaria based on its relationship with the duration of sporogony and is particularly relevant to Plasmodium vivax and P. falciparum (Nikolaev, 1935).…”

Section: 3 Defining the Absence Of Malaria Riskmentioning

confidence: 99%

“…To shrink a map, one has to begin by knowing the map accurately and how it may have changed in the past. Several attempts have been made over the last 60 years to define the limits of malaria transmission using a variety of climate-driven constraints on parasite and vector survival and reported case incidence (Boyd, 1930; Craig et al, 1999; Dutta and Dutt, 1978; Guerra et al, 2006, 2008; Hay et al, 2009; Kiszewski et al, 2004; Le Lannou, 1936; Lysenko and Semashko, 1968; Macdonald, 1957; Manguin et al, 2008; Pampana and Russell, 1955; US War Department, 1944). These mapped products have been difficult to use sequentially to understand the changing margins and intensity of risk as each has used different methodologies and input data.…”

Section: 1 Introductionmentioning

confidence: 99%

The Changing Limits and Incidence of Malaria in Africa

Snow¹,

Amratia²,

Kabaria³

et al. 2012

Advances in Parasitology

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Understanding the historical, temporal changes of malaria risk following control efforts in Africa provides a unique insight into what has been and might be archived towards a long-term ambition of elimination on the continent. Here, we use archived published and unpublished material combined with biological constraints on transmission accompanied by a narrative on malaria control to document the changing incidence of malaria in Africa since earliest reports pre-second World War. One result is a more informed mapped definition of the changing margins of transmission in 1939, 1959, 1979, 1999 and 2009.

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“…During the halcyon days of global malaria eradication, mapping the precise spatial extent of the disease was central to the control efforts of the World Health Organization (WHO). Between the 1940s and 1970s, a huge investment was made in synthesising available information on the distribution of risk using various combinations of expert opinion, elevation, climate, presence/absence records of the disease and vectors, spleen rates, parasite rates, sporozoite rates, biting rates and haemoglobinopathy prevalence (Boyd, 1949; Pampana and Russell, 1955; WHO, 1966; Lysenko and Semashko, 1968; Dutta and Dutt, 1978). Since the 1970s, as the world’s public health focus shifted from malaria eradication, an interest in mapping global malaria risk waned (Carter and Mendis, 2002; Hay et al ., 2004a).…”

Section: Introductionmentioning

confidence: 99%

Defining the Global Spatial Limits of Malaria Transmission in 2005

Guerra

Snow

Hay

2006

Advances in Parasitology

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There is no accurate contemporary global map of the distribution of malaria. We show how guidelines formulated to advise travellers on appropriate chemoprophylaxis for areas of reported Plasmodium falciparum and Plasmodium vivax malaria risk can be used to generate crude spatial limits. We first review and amalgamate information on these guidelines to define malaria risk at national and sub-national administrative boundary levels globally. We then adopt an iterative approach to reduce these extents by applying a series of biological limits imposed by altitude, climate and population density to malaria transmission, specific to the local dominant vector species. Global areas of, and population at risk from, P. falciparum and often-neglected P. vivax malaria are presented for 2005 for all malaria endemic countries. These results reveal that more than 3 billion people were at risk of malaria in 2005.

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Malarial ecology: A global perspective

Cited by 9 publications

References 0 publications

A World Malaria Map: Plasmodium falciparum Endemicity in 2007

A World Malaria Map: Plasmodium falciparum Endemicity in 2007

The Changing Limits and Incidence of Malaria in Africa

Defining the Global Spatial Limits of Malaria Transmission in 2005

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