under the microscope
under the microscope
By Priya Dhagat , MS , MLS ( ASCP ) CM , CIC
Creating Better Anthrax Awareness
Last month , the World Health Organization ( WHO ) reported large anthrax outbreaks in five African countries — Kenya , Malawi , Uganda , Zambia , and Zimbabwe — with more than 1,100 suspected cases and 20 deaths . Zambia reported the largest and most widespread outbreak out of the five countries , with 684 suspected cases , 25 confirmed cases , and four deaths in nine of Zambia ’ s ten provinces . According the WHO report , the outbreak began in the summer within a southern province where 26 people developed sores on their face , arms , and fingers after eating meat from wild hippopotamus carcasses . Cattle , goats , and hippos were reportedly dying from an unknown cause in surrounding areas .
Though anthrax is endemic in these countries , the WHO said the recent uptick in cases is caused by a combination of climate change , food insecurity , and a low perception of risk when handling meat and animal products and a high risk of spread due to frequent movement of animals and animal carcasses between Zambia and its neighboring countries , especially alongside the Zambezi , Kafue , and Luangwa rivers that flow into lakes in Malawi , Mozambique , and Zimbabwe . Numerous response activities have been taken , including active surveillance , health promotion , community engagement , meat inspections , and livestock vaccination .
Anthrax is a disease caused by the spore-forming bacteria Bacillus anthracis . Anthrax spores are extremely stable and resistant to desiccation , heat , ultraviolet light , gamma radiation , and many disinfectants . Spores are found naturally in soil and can remain dormant for years until they find a host that produces key amino acids that stimulate the spores to germinate and become vegetative bacteria . Herbivores , such as sheep , goats , horses and cattle are become infected by ingesting vegetation , soil , or water that is contaminated with B . anthracis spores . Humans can be infected when handling infected animals or contaminated animal products ( e . g ., handling carcasses , butchering or consuming raw or undercooked meat ,
handling unprocessed hides , drumheads , or wool ). Interestingly , infection manifests differently depending on the route of exposure : cutaneous , gastrointestinal , inhalation , and injection .
Cutaneous anthrax is the most common and mildest form and occurs when spores directly enter the body through a cut , sore , or open wound on the skin . Cutaneous anthrax presents as a raised , itchy papule resembling an insect bite that progresses to a lesion that eventually ruptures and becomes an ulcer with a black center , called an eschar .
Gastrointestinal anthrax is the result from ingesting raw or undercooked meat from an infected animal . Once spores germinate in the intestinal tract , a rapid onset of nausea , vomiting , abdominal pain , fever , and diarrhea occur roughly two to five days after infection , eventually leading to ulcerative lesions , hemorrhage , obstruction or perforation . This form of anthrax can affect the throat , esophagus , stomach , and intestines .
Inhalation anthrax is the most lethal form for anthrax . In fact , according the CDC , “ B . anthracis is a Tier 1 select agent and considered one of the most likely bioterrorism agents to be used because it is relatively easy to acquire from the natural environment , mass produce , and disseminate as spores via aerosolization .” Inhaled spores accumulate within the lung alveoli , become engulfed by macrophages , neutrophils , dendritic cells , and are then transported to lymph nodes where the bacteria germinate and produce toxins . During an incubation period of two to 10 days , influenza-like symptoms , fever , and a nonproductive cough develops . Of note , while symptoms of inhalation anthrax usually begin a week after exposure , the incubation period may be prolonged and expand up to two months . Inhalation anthrax can lead to severe dyspnea , hypotension , and septic shock . Without treatment , only 10 - 15 % of people survive .
Injection anthrax is a rare but newer form of anthrax and results in skin and tissue infections associated with injection drug use that is contaminated with B . anthracis spores . It appears as small swollen blisters or eschars and deeper skin abscesses at the injection site .
In the United States , anthrax among livestock is controlled through vaccination programs which has greatly reduced human infections , although wildlife and livestock anthrax infections still occur sporadically in southwest Texas through Colorado , North Dakota , South Dakota , and Montana . Despite the hardiness of the anthrax spore and the different types of anthrax infections , anthrax is not considered to be contagious . According the to the CDC , person-to-person transmission of untreated cutaneous anthrax is possible , but rare . Person-to-person transmission does not occur from pulmonary or gastrointestinal anthrax . In healthcare settings , standard precautions should be followed for all forms of anthrax . Contact precautions are recommended if uncontained copious drainage is present . If a patient is potentially contaminated with spores , they should be isolated in an airborne infection isolation room until decontamination procedures are completed . Healthcare workers should wear appropriate PPE , most importantly a respirator ( N95 mask or Powered Air Purifying Respirators ). Anthrax can be diagnosed by several laboratory methods such as bacterial culture and identification from various specimen types , serology tests , and antigen detection . Infection can be treated with antibiotics based upon anthrax disease manifestation . Refer to the CDC Anthrax Diagnosis page and this CDC MMWR report for more information on diagnostic testing and updated guidelines for prevention and treatment .
Priya Dhagat , MS , MLS ( ASCP ) CM , CIC , is an infection preventionist and the associate director of the system-wide Special Pathogens Program within the Department of Emergency Management at New York City Health + Hospitals , overseeing special pathogen preparedness and response efforts across New York City Health + Hospitals frontline healthcare facilities . Additionally , she supports and offers subject matter expertise for infection prevention topics for the National Emerging Special Pathogens Training and Education Center ( NETEC ).
8 • www . healthcarehygienemagazine . com • january 2024