WATERBORNE PATHOGENS WATERBORNE PATHOGENS OF CONCERN IN OF CONCERN IN

DEVELOPING COUNTRIES:DEVELOPING COUNTRIES:

with Special Reference to Libyawith Special Reference to Libya

Prof. Khalifa Sifaw GhengheshProf. Khalifa Sifaw GhengheshDept. of Medical Microbiology, Dept. of Medical Microbiology,

Faculty of MedicineFaculty of MedicineTripoli - LibyaTripoli - Libya

INTRODUCTION

Drinking water is a major source of microbial pathogens in developing countries.

Waterborne disease cause more than 2 million deaths and 4 billion cases of diarrhea annually.

9 out of 10 deaths are in children and virtually all of the deaths are in develop-ing countries

WATERBORNE PATHOGENS INWATERBORNE PATHOGENS INDEVELOPING COUNTRIESDEVELOPING COUNTRIES

BACTERIA

Microorganism Major disease---------------------------------------------------------------------------Salmonella typhi Typhoid feverS. paratyphi Paratyphoid feverOther Salmonella SalmonellosisShigella spp. Bacillary dysentery

(Shigellosis)Vibrio cholerae CholeraDiarrheagenic E. coli GastroenteritisYersinia enterocolitica GastroenteritisCampylobacter jejuni GastroenteritisAeromonas spp. GastroenteritisVarious mycobacteria Pulmonary illness

ENTERIC VIRUSES

EnterovirusesPolio viruses PoliomyelitisCoxsackie A & B Aseptic meningitisOther enteroviruses Encephalitis

Rotavirus Gastroenteritis

Adenoviruses Upper respiratory and gastrointestinal illness

Hepatitis A & E viruses Infectious hepatitis

Norovirus Gastroenteritis

PROTOZOA & HELMINTHS

Balantidium coli Balantidosis (dysentery)

Cryptosporidium parvum Cryptosporidiosis

(gastroenteritis)

Entamoeba histolytica Amoebic dysentery

Giardia lamblia Giardiasis (gastroenteritis)

Ascaris lumbricoides Ascariosis

Causative Agents of Childhood Diarrhea in Libya

% positiveAgent Tripoli Benghazi Zliten--------------------------------------------------------------------------------------------------

-Single 41 35 44Multiple 19 6 12Rotavirus 32 24 27Salmonella 11 7 14Shigella 6 5 4Enteropathogenic E. coli 11 8 NDE. coli O157 7 ND NDCampylobacter 6 2 NDYersinia enterocolitica 0.6 0 NDAeromonas 15 0 6Cryptosporidium ND ND 13Giardia lamblia ND ND 1Entamoeba histolytica ND ND 12

Bacteriological Quality of Drinking Water in Libya

Type of No % positive for

Water tested E. coliAeromonas

----------------------------------------------------------------------

Well 1000 37 49

Fasghia 56 27 73

Majin 62 ND 60

From Mosques 50 14 18

Mineral 216 0 0

Outbreaks of waterborne disease in England and Wales from 1991 to 2000

Cause Number of Number Outbreaks of cases

----------------------------------------------------------------------------------------------------------

Public water supplies:Cryptosporidium 23 2837Campylobacter 1 281Gastroenteritis 1 229

Total 25 3347

Private water supplies:Campylobacter 8 178Mixed Campylobacter 1 43and CryptosporidiumCryptosporidium 3 74Gastroenteritis 2 81Giardia 1 31E. coli O157 1 14

Total 16 421

Recreational contact with surface waterViral gastroenteritis 1 7

Swimming pool contactCryptosporidium 23 337

----------------------------------------------------------------------------------------------------------

Overall total 65 4112

Outbreaks of waterborne disease in Tripoli1992-2004

Number of Number outbreaks of

cases

---------------------------------------------------------------------------------

Public water supplies:

Shigella sonnei 1 >1500

Private water supplies:

Shigella flexneri 1 6

Some Concerns Regarding Waterborne Pathogens

Efficacy of treatment (filtration and chlorination) and the use of E. coli as a fecal indicator: Chlorine-resistant parasitic protozoa

• Oocysts of Cryptosporidium parvum Various enteric viruses

Important to match the appropriate indicator for the group of pathogen(s) of interest.

Emerging Waterborne Issues

Rapid urbanization of humans in developing regions:

Places further stress on inadequate water supply and sanitation.

Climate change: A change in the distribution of rainfall

• Heavy rain fall• Flooding

Greater extremes in global weather patterns• Major waterborne outbreaks typically follow large storm

events in developing countries

Evolution of new pathogens

What We Should Do?

A combination of both monitoring of water quality and epidemiological surveillance.

A comprehensive public health surveillance strategy seems the most efficient approach to better understand and control the impact of water quality on gastrointestinal disease.

CONCLUSION

Despite our efforts, waterborne pathogens will

always be a major issue for human health, and

particularly so in developing countries