6 major factors leading to reemergence of infectious diseases
(1) changes in human demographics and behavior
(2) advances in technology and industry
(3) economic development and changes in land use
(4) Ý
in international travel and commerce
(5) microbial adaptation and change
(6) breakdowns in public health measures.
Recommendations for controlling infectious diseases
strengthen infectious disease surveillance
identify applied research needs and training priorities
target vaccine, drug, and pesticide development needs
promote public education programs to effect behavioral changes.
1993 Outbreak of E. Coli 0157:H7
Demographics
Þ January 1993 in Western U.S. (Wash, Idaho, Nevada, Calif); largest ever outbreak of E. Coli 0157:H7 infection; 56 people with HUS and 4 deaths.
Source of outbreak
Þ Hamburgers from a fast-food restaurant.
Symptoms of infection
Þ frequent bloody diarrhea with severe abdominal cramps and little or no fever; HUS (hemolytic uremic syndrome) is most important complication and leading cause of acute renal failure in children in U.S.
Modes of organism transmission
Þ food (ground beef), water, and person-to-person.
Factors contributing to its emergence
Þ single hamburger patty includes meat from many cattle; fast food restaurants with uniform methods of preparation and single sources of food Ý opportunity for large scale contamination of population; widespread and Ý use of child daycare centers favor transmission.
1993 Outbreak of Cryptosporidiosis
Demographics
Þ Spring 1993 in Milwaukee; largest ever outbreak of waterborne infection; 403,000 ppl became ill.
Source of outbreak
Þ Milwaukee Municipal water supply due to inadequate filtration (high turbidity).
Symptoms of infection
Þ watery diarrhea (39% attack rate) lasting 10 days in immunocompetent accompanied by cramping abdominal pain, N/V, malaise and low-grade fever; No longer self-limiting if immunocompromised (AIDS).
Modes of organism transmission
Þ contaminated water; direct contact with feces of infected animals; person-to-person via fecal-oral route (child day care setting).
Factors contributing to its emergence
Þ heavy rains, winter snow melt, and run off from dairy farm lands Ý the conc. of oocysts in Lake Michigan; changes in the coagulation step of the Citys water treatment; Parasite is resistant to chlorine and must be removed by mechanical methods such as filtration.
1993 Outbreak of Hantavirus Pulmonary Syndrome
Demographics
Þ May 1993 in New Mexico; due to a new strain of Hantavirus (previous strains = Hantaan, Seoul, Puumala, Prospect Hill).
Source of outbreak Þ
Deer mice (Peromyscus maniculatus) which are found in all parts of the country except the SE
Symptoms of infection Þ
acute, often fatal (58% mortality), pulmonary syndrome in adults; hemorrhagic fever with renal syndrome.
Modes of organism transmission Þ
Rodents are natural hosts for all hantaviruses; exposure to rodent excreta, either through the aerosol route or direct inoculation; no evidence of person-to-person transmission.
Factors contributing to its emergence Þ
Heavier than normal rainfall leading to abundant food sources and underbrush Ý the population of infected mice in 1993.
New Forms of Old Entities
Influenza
will soon have a new pandemic with no age discrimination
Lyme disease
lead to an epidemic of arthritis in young children
HIV
HIV1 in the U.S. and HIV2 in Africa
Helicobacter
cause of gastrointestinal infections and ulcers, also linked to malignancies
Wipples disease
now found to be due to Torpherema wippleya
Camplyobacter enteritis
rare cause of diarrhea, now known to precede Guillan burr`e (unknown mechanism)
E. Coli
one of most abundant organisms in intestinal tract