Differential Diagnosis Pneumonic Plague Septicemic Plague Inhalation anthrax

Differential Diagnosis Pneumonic Plague Septicemic Plague ■ Inhalation anthrax ■ Meningococcemia ■ Tularemia ■ Septicemia caused by other Gram-Negative Bacteria ■ Viral Pneumonia Influenza, Hantavirus, RSV, CMV ■ Other Bacterial Pneumonia ■ Q Fever

Diagnosis Suspected Plague Both of the following conditions are met: 1. Clinical symptoms of Plague in person who resides in or has recently traveled to a plague-endemic region 2. Smear* taken from affected tissues shows small gram-negative and/or bipolar-staining coccobacilli (Polychromic stains: Wright, Giemsa, or Wayson stain ) * Sample taken from Bubo (bubonic plague), Blood (septicemic plague), or Tracheal/lung aspirate (pneumonic plague)

Diagnosis Presumptive Plague One or both of the following conditions are met: 1. Immunofluorescence stain of smear +ve for the presence of Yersinia pestis F 1 antigen. 2. Only a single serum specimen is tested & the anti-F 1 antigen titer by agglutination is >1: 10. * *Agglutination testing must be shown to be specific to Y. pestis F 1 antigen by hemagglutination inhibition.

Diagnosis Confirmed Plague One of the following conditions is met: 1. Isolated culture lysed by specific bacteriophage. 2. 2 serum specimens demonstrate a 4 fold anti-F 1 antigen titer difference by agglutination testing. * 3. Single serum specimen tested by agglutination has a titer of >1: 128 and the patient has no known previous plague exposure or vaccination history. * *Agglutination testing must be shown to be specific to Y. pestis F 1 antigen by hemagglutination inhibition.

Treatment Isolation: ■ For the first 48 hours following treatment, in case pneumonia develops ■ By law, patients with pneumonic plague must be isolated ■ If patients have no pneumonia or draining lesions at 48 hours, they may be taken out of strict isolation. Antibiotics: ■ For a minimum of 10 days (or 3 -4 days after clinical recovery)

Antibiotic Therapy Adult Child Pregnant ♀ Streptomycin * 1 g IM or IV x 1/day * 15 mg/kg IM x 2/day -------------- Gentamicin * 5 mg/kg IM or IV x 1/day * 2. 5 mg/kg IM or IV x 3/day * 5 mg/kg IM or IV x 1/day Doxycycline 100 mg IM x 2/day or 200 mg IV x 1/day 2. 2 mg/kg IV x 2/day 100 mg IV x 2/day or 200 mg IV x 1/day Ciprofloxacin 400 mg IV x 2/day 15 mg/kg IV x 2/day 400 mg IV x 2/day Chloramphenicol 25 mg/kg IV x 4/day (but not if < 2 years of age) -------------- *Preferred Treatment (others are alternatives)

Antibiotics – Mechanism of Action

Prognosis Fatality Bubonic 1 or 2 Septicemic Untreated 1 or 2 Pneumonic 100% 50%-90% 50%-100% Treated most within 48 hrs of onset ? 5%-20% 30%-50% treatment must begin w/i 18 hrs of onset 1 Pneumonic Plague progresses the most rapidly

Prevention ■ Education on modes of transmission ■ Integrated Vector Management (surveillance of animal reservoirs) ■ Control Rat & Flea Populations ( traps, insecticides) San Jose, CA; 1991

Prevention Personal Sanitation Measures ■ Veterinary workers in endemic areas: gloves, eye protection, surgical masks when treating suspect cats ■ Hunters and Outdoorsmen: avoid rodent nests, use insect repellents/insecticides, wear gloves when handling potentially infected animals ■ In the Lab: - Standard Control: when handling Y. Pestis organisms - Biosafety Level 2: when processing clinical specimens & cultures - Biosafety Level 3: with large amounts of bacteria or with potential for aerosolization

Prevention Existing Vaccines – None Available for Use! Vaccine Strategy Status Remarks EV 76 Live Attenuated Mutant Strain Introduced in 1908 - Not avirulent - Questionable Safety - No protection Pnemonic form Formalin. Inactivated Whole Cell Manufactured 1940 -1999 Limited availability in former Soviet Union USP No Longer Available - Induces F 1 antigen response - Not tested in controlled studies - Severe inflammatory reactions - Multiple Booster Shots - No protection Pneumonic form

Prevention Improved Vaccines – In Development Vaccine Strategy Status Remarks F 1/V Fusion Protein Recombinant Subunit Preclinical testing in mice and nonhuman primates - Effective in aerosol challenge in mice & monkeys F 1/V Combo Recombinant Subunit Phase 1 clinical trials completed (phase 2 trials due to begin in late 2002/early 2003) - 2: 1 F 1/V ratio - Protection via Ig. G - Also F 1 V-specific Ig. A response - Adjuvanted with alhydrogel - Protection Bubonic & Pneumonic DNA Preclinical testing in mice -mice: immunization plus booster shot with recombinant antigens developed protective immunity against lethal dose (separate proteins) V antigen in Plasmid DNA construct

Prevention Prophylactic Antibiotics ■ only following high-risk exposure to pneumonic plague Adult Child Pregnant ♀ Doxycycline * 100 mg PO x 2/day * * 2. 2 mg/kg POx 2/day 100 mg PO x 2/day Ciprofloxacin * 500 mg PO x 2/day * * 20 mg/kg PO x 2/day 500 mg PO x 2/day Chloramphenicol 25 mg/kg PO x 4/day (not < 2 yrs of age) 25 mg/kg PO x 4/day *Preferred Treatment (others are alternatives) ■ treat for 10 days (if fever/cough develops during prophylactic treatment, then follow standard therapy for Y. Pestis)

Caution: Drug Resistant Strains in Patients Y. Pestis Strain Isolated 16/95 17/95 Drug Resistance How New Genes Madagascar, Streptomycin 1995 streptomycin phosphotransferase Genes in the acquired selftransferable plasmid p. IP 1203 Madagascar, 1. Ampicillin 1997 2. Chloramphenicol 3. Kanamycin 4. Minocycline 5. Streptomycin 6. Spectinomycin 7. Sulfonamides 8. Tetracycline 1. production Lactamase 2. Production chloramphenicol acetyltransferase 3. synthesis of a type I 3'aminoglycoside phosphotransferase 5. & 6. 3''-9 Aminoglycoside adenylyltransferase Genes in the acquired conjugative plasmid p. IP 1202

Weaponization of the Plague

History of Weaponization n Mongols throw plague infected bodies over the walls of the besieged city of Kaffa in 1346 n In WWII, Japanese army dropped Plague-infected fleas packed into bombs over Manchuria and infected their water supply resulting in an outbreak. n During The Cold War, the U. S. and Soviet Union developed methods of aerosolizing Plague-thereby eliminating the flea vector.

CDC Classification of Plague n Plague is in Category A, it is a highpriority organism n High-priority agents include organisms that pose a risk to national security because: n n can be easily disseminated or transmitted from person to person result in high mortality rates and have the potential for major public health impact might cause public panic and social disruption require special action for public health preparedness

Plague is a Suitable Pathogen For Use As a Weapon Because… n It is accessible, simple to reproduce, economical and efficient. n It can be delivered in aerosol form n Pneumonic plague causes serious illness with a high case fatality rate n Pneumonic plague is communicable n 100 -500 bacteria are enough to cause pneumonic plague, whereas it takes between 1, 000 -10, 000 spores to cause pulmonary anthrax

Are We Prepared? n A 1970 WHO report estimated that an aerosol release of 50 kg of Y. Pestis over a city of 5 million people would produce 150, 000 illnesses and up to 36, 000 deaths. (This report didn’t take into account the secondary cases that would occur through person-toperson contact. n A simulated bioterror attack (TOPOFF) involving aerosolization of the plague was carried out in May 2001, in Colorado. By the end of the third day, 783 people had contracted pneumonic plague, by the next day the number of plague cases had risen to 1, 871 and by the third day the number stood at 3, 060. At the end of the exercise 950 people had “died” of pneumonic plague.

In The Event of An Attack… n Early treatment with antibiotics (gentamicin, streptomycin, tetracycline, fluoroquinoline) n Use of surgical masks to prevent further transmission.

The Bad News… Resistance n Sequence of Y. pestis could have boomerang effect, enabling terrorists to create antibiotic resistant strands. n According to Alastair Hay, the Soviet Union has already developed a form of Yersinia pestis that was resistant to 16 different antibiotics. n Right: Picture of Staphylococcus Aureus next to Y. Pestis. A transfer of antibiotic resistant genes from Staph to Y. Pestis could result in a uncontrollably lethal bacterium.

The Good News… n Requires a high level of knowledge to distinguish between virulent and non-virulent strain, efficiently produce the virulent strains, and aerosolize it. n Plague bacteria is a fragile organism because it is non-spore forming, so it can only remain viable for only about 1 hr after aerosolization.