A world view

From:  http://www.stanford.edu/class/humbio153/InteractiveMaps/index.html

SOME BASIC CONCEPTS 

A Picture Painted with a Broad Brush

Parasitic infections are relatively rare in the United States. Why? Because most Americans:

1.     Can afford shoes;

2.     Have adequate nutrition, at least relative to calories and protein;

3.     Have access to a water supply that is not contaminated with raw sewage;

4.     Have adequate access to health care resources (medical professionals, nearby hospitals, antibiotics, drugs, vaccines);

5.     Use synthetic fertilizers to grow crops, as opposed to human nightsoil;

6.     Life in the temperate zone, where there is a season during which insect vectors are absent.

So? People live long enough to show diseases of degeneration, such as:

·        Cancer: ~ 400,000 deaths per year

·        Heart disease: ~ 800,000 deaths per year

 

This is NOT the case in 3rd World Countries:

World Life Expectancy
http://www.worldlifeexpectancy.com/

 

 

TABLE 1.  ESTIMATES OF THE NUMBERS OF HELMINTH INFECTIONS IN MAN.

(ADAPTED FROM PETERS AND GILLES, 1977; PETERS, 1978 and Schmidt & Roberts, Foundations of Parasitology, ed. 5, 1996)

 

INTESTINAL NEMATODES                    MILLIONS           Deaths per Year

All helminths                                                        3500

Ascaris lumbricoides                                             1250                     20,000

Hookworm (Necator sp., Ancylostoma spp.)                 950            50,000-60,000

Trichuris trichiura                                                 700

Enterobius vermicularis                                         350

Strongyloides stercoralis                                          60

 

TISSUE NEMATODES

Wuchereria bancrofti                                                       350

Dracunculus medinensis                                          80

Trichinella spiralis                                                   50

Onchocerca volvulus                                                40

Loa loa                                                                    20

 

TREMATODES

Schistosoma spp.                                                   300            500 K to 1 million

Clonorchis sinensis                                                  40

          Fasciolopsis buski                                          15

          Paragonimus westermanni                               5

 

CESTODES

          Taenia spp.                                                   80

          Hymenolepis Spp.                                          40

          Diphyllobothrium latum                                 15

                                                                   

 

PROTOZOA

(From Markell & Voge:  Medical Parasitology)

          Entamoeba histolytica                                   600

          Plasmodium Spp.                                         489           1-2 million

          African trypanosomiasis                                          35

          American trypanosomiasis                             10

 

In 1986, there were an estimated 60 million deaths, of which 30 million are children <5 years old.  Half of the deaths among children (15 million) were due to a combination of malnutrition and intestinal infection.