Overview Existing, Emerging, and Re-Emerging Communicable Diseases

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1 Overview Existing, Emerging, and Re-Emerging Communicable Diseases Many communicable diseases have existed with us since the beginning of time. Communicable diseases, which are infections we catch from others including animals in the environment, have long been the cause of human illness, injury and death. Over the last century, the discovery of antibiotics increased treatment options. More individuals now recover from communicable diseases which has contributed to the increased life span. Emerging diseases can result as humans alter and/or enter environments that they had not previously used and as technology allows for detection. During the past 30 years at least 30 new viral, bacterial and parasitic diseases have been classified as emerging. Examples of emerging diseases are: hantavirus, ebola virus and E. Coli 0157:H7. Re-emerging communicable diseases are those which may recycle through different geographic areas or population groups. Diseases may mutate or evolve as a result of biological tendency, environmental conditions, or as a response to antimicrobial drugs. Examples include: tuberculosis and antibiotic-resistant streptococci infections. Wisconsin statutes require that communicable diseases be reported to the local health agency for follow up. Category I diseases are of urgent health importance and shall be reported immediately by telephone. Examples of category I diseases are: anthrax, foodborne or waterborne outbreaks, hepatitis A, measles, meningococcal disease, pertussis and tuberculosis. Category II diseases shall be reported within 72 hours of the identification of a case or suspect case. Examples of category II diseases are: giardiasis, cryptosporidiosis, hepatitis B and C, sexually transmitted diseases, and E. Coli 0157:H7. Category III, which includes AIDS and HIV, are reported to the state epidemiologist. For this community assessm ent, we will look at selected disease reports in Chippewa County, excluding Sexually Transmitted Diseases assigned for review by the high risk sexual behavior workgroup. It is generally believed there are more cases yearly than noted here as communicable disease cases are unreported. Gastrointestinal Communicable Diseases Gastrointestinal infections cause infection of the stomach and intestines through swallowing or eating. Some reported gastrointestinal diseases have shown an overall decline from 1995 through 2001, as noted in the graph below.

2 As noted on the previous graph, Giardiasis, a microscopic parasite, is the most reported cause of diarrheal illness in Wisconsin. Campylobacteriosis causes a bacterial infection and is the most commonly reported cause of bacterial diarrhea in Wisconsin. Salmonellosis is also a gastrointestinal bacterial infection. E. Coli 0157:H7, which is often linked with undercooked meat, is an intestinal bacteria which produces a toxin. Local declines over 6 years may be due to fewer reports, improved food handling and preparation. Reported cryptosporidiosis cases are on the rise. Cryptosporidiosis case reports increased from 1995 through The cryptosporidum protozoa, a single-celled parasite, was recognized as a cause of human disease beginning in The number of reported cases for other gastrointestinal diseases have been sporadic in Chippewa County from 1995 through 2001 as noted below: 2

3 Hepatitis A is the type of hepatitis known to spread through the oral-fecal (hand to mouth) route. This viral infection causes a liver disease which is communicable and may be associated with a foodborne outbreak. Shigellosis is a bacterial infection which occurs most often in young children. Respiratory Communicable Diseases Respiratory infections are a major cause of death and disability in Chippewa County. Respiratory infections are spread through coughing, sneezing and talking when droplets of moisture with the infection transfer from one person enter another. The above graph shows two different kinds of reported bacterial infections. Mycobacterium, non-tuberculosis, tends to be an infection of older adults with other health problems. Legionnaires Disease has been associated with improperly installed or handled ventilation system. There was one actual case of tuberculosis diagnosed in Chippewa County in the time period; 218 tuberculosis (TB) skin tests were administered by public health nurses in 2001 and none were positive. While not all meningitis and encephalitis is spread through the respiratory tract, it is a significant entryway for these infections. 3

4 More cases of viral and bacterial meningitis have been reported in 2001 as compared to 1995, with bacterial causes showing a regular steady increase. Viral encephalitis has also been sporadically reported. Emerging diseases, such as the West Nile Virus transmitted via mosquitoes are also a new concern. Influenza cases are reported as part of our overall monitoring of the incidence in our community. The health department receives the initial report at the beginning of the flu season. There are many more cases of influenza then what is reported. Tickborne Diseases While not communicable from person to person, some diseases cause human illness through the bite of a tick, which is a carrier. Lyme Disease is one such infection which is common in Chippewa County, as shown in the graph to the left. Surveillance for Lyme disease began in Vaccine-Preventable Diseases Ehrlichiosis is another tickborne disease which is beginning to appear in Chippewa County with an average of one case per year. Immunizations can prevent spread of some communicable diseases. There are currently effective vaccines offered by the health department against: measles, mumps, rubella, polio, diphtheria (whooping cough), hepatitis B, tetanus, haemophilus influenzae type B, varicella (chickenpox), influenza and some causes of pneumonia. The following doses of vaccine were given by the health department in 2001; IMMUNIZATION NUMBER OF DOSES Diphtheria/Tetanus/Acellular Pertussis (DTaP) 361 Hepatitis B 1,740 Hepatitis B and Haemophilus Influenzae B (Comvax) 129 Haemophilus Influenzae B (PedvaxHIB) 36 Measles Mumps Rubella (MMR) 228 Pneumococcal Polysaccharide (Pneumovax 23) 41 Influenza 1,652 Pneumococcal (Prevnar) - children 140 Polio (Injectable) 330 Tetanus diphtheria (Td) - adult 104 Varicella (chickenpox) 154 4

5 There was one case of tetanus reported in Chippewa County in At least one pertussis ( whooping cough ) case has been reported annually except for 1998 and Eight cases were reported this year through July Nationwide shortages or delays in vaccine delivery for adult Td, varicella, influenza and Prevnar (children s pneumococcal vaccine) has resulted in postponement, prioritization, or altered scheduling of certain vaccines which may impact the incidence of vaccine-preventable diseases. Prevnar remains in short supply. Chickenpox cases dropped from 43 in 2000 to 2 in 2001, which may be attributable to more children being vaccinated and the WI immunization law which requires it for school admission (Chippewa County Dept of Public Health Annual Report 2001). In the school year, 99.2% of Chippewa County school children were up to date on immunizations (Chippewa County Dept of Public Health Annual Report). Three cases of Haemophilus Influenzae infection were reported in A vaccine given to children up to age 15 months is protective against this disease. Bloodborne Communicable Diseases Transmission of infections can occur through person-to-person exposure to blood and blood products. Entry for the infection may be through mucous membranes, open cuts or other exposure to blood. Reported cases of Hepatitis B have generally declined or remained unchanged over the six year period. On the other hand, reported cases of Hepatitis C are on the increase. There is no Hepatitis C vaccine. Other Specific Notes about Communicable Diseases In 1997, Chippewa County had the only reported case in Wisconsin of hantavirus infection. The cause was from exposure to rodent droppings. Sampling of the local rodent population determined a small percentage were carriers. Of the reported cases since 1995, there have been seven deaths due to the communicable disease. Five deaths were due to bacterial meningitis. World events over the past year have shown the potential threat of infectious agents used for bioterrorism. While no confirmed event occurred in Chippewa County, the possibility of bioterrorism with anthrax, smallpox or other infectious agents is one for which we must be prepared. A summary report of Communicable Disease Reports to the Health Department, through July 2002 follows. 5