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ZOONOSIS
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INTRODUCTION• Zoonoses :- derived from the Greek words
• Zoon- Animal & Noson – Disease
• Zoonoses was coined and first used by Rudolf Virchow who defined it for communicable diseases
• Diseases and infections which are naturally transmitted between vertebrate animals and humans - WHO 1959
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• Of the 1415 microbial diseases affecting humans, 61% are zoonotic with 13% species regarded as emerging or reemerging.
• Link b/w human & animals with their surrounding are very close especially in developing countries.
• Emerging zoonosis as “a zoonosis that is newly recognized or newly evolved, or that has occurred previously but shows an increase in incidence or expansion in geographical, host or vector range”-WHO/FAO/OIE joint consultation, May 2004
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• Emerging infectious disease-
Hanta virus in USA
Avian influenza
Bovine Spongiform Encephalitis (BSE)
Nipah virus.
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Factors Influencing The Emergence of Zoonotic Diseases
Etiological changes in mans environment and agricultural operations e.g. Leptospirosis, plague, Rift Valley fever, Kyasanur Forest Disease etc.
Increased movement or traveling of man e.g. amoebiasis, giardiasis, colibacillosis, salmonellosis, SAARS, Yellow fever etc.
Handling animal byproducts and waste e.g. anthrax, chlamydiosis, dermatophytosis, tularaemia
Increased in density of animal population e.g. dermatophytosis, tuberculosis etc.
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Increased trade in animal products e.g. anthrax, brucellosis, salmonellosis, Hantaan virus, Bird flu etc.
Drug resistant organisms e.g. E.coli, Staphylococcus aureus etc.
Changing livestock farming practices e.g. E.coli O157:H7, Salmonellosis, Listeriosis etc.
Changing environmental conditions including climate and disaster e.g. plague, Leptospirosis etc.
Pathogen changes like genetic shift and drift e.g. Influenza, E.coli, Staphylococcus
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Classification Of Zoonoses
According to the Etiological agents Bacterial zoonoses e.g. anthrax, brucellosis, plague, leptospirosis,
salmonellosis, lyme disease Viral zoonoses e.g. rabies, arbovirus infections, KFD, yellow fever,
influenza
Rickettsial zoonoses e.g. murine typhus, tick typhus, scrub typhus, Q-fever
Protozoal zoonoses e.g. toxoplasmosis, trypanosomiasis, leishmaniasis
Helminthic zoonoses e.g. echinococcosis (hydatid disease), taeniasis, schistosomiasis,dracunculiasis
Fungal zoonoses e.g. deep mycosis - histoplasmosis, cryptococcosis, superficial dermatophytes.
Ectoparasites e.g. scabies, myiasis9/23/2015
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According to the Mode of transmission
• Direct zoonoses- From an infected vertebrate host to a susceptible host (man) by direct contact, by contact or thru fomite e.g. rabies, anthrax, brucellosis, leptospirosis, toxoplasmosis.
• Cyclozoonoses - Require more than one vertebrate host species, but no invertebrate host for the completion of the life cycle of the agent, e.g. echinococcosis, taeniasis.
• Metazoonoses - Transmitted biologically by invertebrate vectors, in which the agent multiplies and/or develops & there is always an extrinsic incubation (prepatent) period before transmission to another vertebrate host e.g., plague, arbovirus infections, schistosomiasis, leishmaniasis.
• Saprozoonoses -Require a vertebrate host & a non-animal developmental site like soil, plant material, pigeon dropping etc. for the development of the infectious agent e.g. aspergillosis, coccidioidomycosis, cryptococosis, histoplasmosis, zygomycosis
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According to the reservoir host
• Anthropozoonoses - Infections transmitted to man from lower vertebrate animals e.g. rabies, leptospirosis, plague, arboviral Infcn , brucellosis and Q-fever.
• Zooanthroponoses - Infections transmitted from man to lower vertebrate animals e.g. streptococci, staphylococci, diphtheria, enterobacteriaceae, human tuberculosis in cattle and parrots.
• Amphixenoses - Infections maintained in both man and lower vertebrate animals and transmitted in either direction e.g. salmonellosis, staphylococcosis
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RABIES
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RABIES
• Acute, highly fatal viral disease of the central nervous system caused by Rabies virus
• In India , rabies account to about 20,000 deaths annually. 1
• Most animal bites in India (91.5%) are by dogs, of which about 60% are strays and 40% pets.
• Rabies is present throughout the country, except in the islands of Lakshadweep & Andaman and Nicobar.
• Incubation Period:- 3-8 weeks
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1. Sudharshan et al. A community survey of dog bites, anti-rabies treatment, rabies and dog population management in Bangalore city. J. Commun. Dis. 38 (1) 2006 :32-39
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• C/f pain and tingling at site of the bite. This is followed by intolerence to noise and bright light. Aerophobia is present.
• Increased reflexes, muscle spasms, dilation of pupils and increased perspiration, salivation & lacrimation are present.
• Hydrophobia is pathognomonic of rabies. Paralysis, coma or sudden death may ensue.
• Prognosis:- Untreated, the fatality rate is 100%. Postexposure treatment is effective until day 6 post-infection
• Antirabies vaccine before clinical onset of symptoms. Postexposure treatment with rabies immune globulin & vaccine
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BRUCELLOSIS
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Brucellosis• Also called Bang's disease, Crimean fever, Gibraltar fever, Malta fever, Maltese
fever, Mediterranean fever, rock fever, or undulant fever.
• Caused by bacterium Brucella (B. melitensis, B. abortus, B. suis, B.canis)
• Most human infections are caused by Brucella melitensis species in India.
• It is highly contagious zoonosis caused by ingestion of unsterilized milk or meat from infected animals or close contact with secretions.
• C/F – Acute brucellosis prolonged bacteraemia, irregular fever, chills, muscular & articular pains, nocturnal drenching sweats, exhaustion, anorexia, constipation, nervous irritability.
• Chronic brucellosis Sweating, lassitude, joint pains with minimal or no pyrexia
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• Blood cultures should be done which yields 40-70% positivity.
• PCR – ELISA has superior specificity and sensitivity
• Prevention of human brucellosis eradication of disease in animals by vaccination, boiling milk before consumption & pasteurization of milk.
• Treatment:- Antibiotic combination: streptomycin, tetracycline, and sulfonamides
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PLAGUE
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PLAGUE• Deadly infectious disease that is caused by the enterobacteria Yersinia
pestis
• Ancient disease and has caused 3 pandemics since 6th century.
• India fatal outbreaks in 1994 and 2002 in Maharashtra and Simla respectively.
• Transmitted by black rat (Rattus rattus) and oriental rat flea (Xenopsylla cheopis).
• Transmission by droplet contact, direct physical contact, by soil contamination, airborne transmission, fecal-oral transmission and vector borne transmission carried by insects or other animals.
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• C/f- Fever, chills, weakness, headache, and swollen, tender lymph nodes (buboes) of inguinal and femoral regions. Marked edema, swelling, & inflammation of tissues overlying the buboes are frequently seen.
• Symptoms begin approximately 2 to 8 days after exposure
• Complications DIC, meningitis, & multi organ failure .
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DIAGNOSIS
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• Hand-held immunochromatographic test are being used rapid bedside test even in remote areas.
• Prevention:- Aggressive rodent population control
• Treatment :-Gentamicin 5 mg/kg iv OD, Streptomycin 2 gm im BD, Doxycycline 200mg PO OD, Tetracycline 2gm iv/PO q6th hrly, Chloramphenicol 50mg/kg PO/ iv Q 6th hrly.
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LEPTOSPIROSIS
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Leptospirosis
• Emerging global public health problem
• Caused by Leptospira interrogans naturally seen in rodents
• Endemic in Andaman Islands & southern states of India (Kerala TN, Gujarat, Karnataka, and Maharashtra)
• Rodents, domestic & wild animals form the reservoir of infection
• Domestic animals such as cattle, dogs, and pigs may act temporary carrier
• Rodents permanent carrier
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• Transmission- excreted in the urine of the animals- humans through direct contact
• C/fconjunctival suffusion, pharyngeal erythema without exudate,muscle tenderness, rales on lung auscultation or dullness on chest percussion over areas of pleural hemorrhage
• Weil’s syndrome jaundice, renal failure and myocarditis with cardiac arrhythmias, pulmonary haemorrhage with respiratory failure
• Diagnosis- Weil's disease sed RFT values levels ,mixed conjugated and unconjugated hyperbilirubinemia with aminotransferase elevation to less than five times the upper limit of normal.
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• Isolation of leptospirosis by culture of blood, CSF and urine -media used is EMJH medium.
• Gold standard- Microscopic Agglutination Test (MAT)- serovar specific test • Other genus specific tests are the ELISA, Macroscopic slide agglutination
test(MSAT), latex agglutination test, Dipstick tests (Lepto dipstick, Lepto Tek lateral flow) and Lepto Tek Dri-Dot test.
• Treatment Mild leptospirosis- Doxycycline 100mg PO BD or Amoxicillin 500mg PO TDS, Moderate/ severe leptospirosis- Ceftriaxone 1gm/ day iv or penicillin (1.5 million units IV or IM q6h) or Cefotaxime (1 g IV q6h), Chemoprophylaxis- Doxycycline (200 mg PO once a week) or Azithromycin (250 mg PO once or twice a week)
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RICKETTSIAL INFECTIONS
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RICKETTSIAL INFECTIONS
• They cause irreversible damage to the human host associated with high morbidity & mortality.
• Mortality rate can be as high as 20 – 50 %.
• Prevalent in J&K, Himachal Pradesh, Uttaranchal, Rajasthan, Assam, WB, Maharashtra, Kerala and TN
• The zoonotic diseases considered important in India are Epidemic typhus, Murine typhus, Scrub typhus, Indian tick typhus and Q fever
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Scrub Typhus
• Causative agent- O. tsutsugamushi
• Transmission- Bite of infected larval mites
• C/f - High Fever, chills, headache, malaise, macular rash, generalized lymphadenopathy, Eschar
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• Diagnosis- Immuno Fluorescent Assay, indirect immunoperoxidase & enzyme immunoassays. PCR amplification of Orientia genes from eschars and blood is also effective
• Treatment:- Doxycycline (100 mg bid orally for 7–15 days), Azithromycin (500 mg orally for 3 days), or Chloramphenicol (500 mg qid orally for 7–15
days).
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ARBOVIRAL DISEASE
• Arboviruses in India Japanese encephalitis virus, Dengue virus & Chikungunya fever
• Globally- Approx 2.5 billion people live in dengue-risk regions with about 100 million new cases each year.
• India accounts for nearly one-third of all dengue cases reported globally
• In 2006 more than 1.3 million people were affected by Chikungunya virus which prevailed across 150 districts of 8 states in India.
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DENGUE FEVER• Also known as break bone fever
• TransmissionBite of Aedes aegyptii bite during day esp early morning & in the evening.
• C/f- Saddle back fever, headache, retrobulbar pain, morbiliform rash appears on trunk & spreads centripetally to face, trunk & limbs. Fever lasts for 5-7 days
• Lab:- Leucopaenia & neutropaenia. Thrombocytopenia occurs b/w 3rd and 8th day.
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• Complications- Dengue Haemorrhagic Fever & Dengue Shock syndrome, ARDS
• Diagnosis- Dengue NS1 antigen (+ve in the first week of illness),IgM antibody detection (ELISA within 2-5 days of illness till 1-3 months)
• Treatment- Symptomatic management
• Anti- Dengue day observed every year on June 15th
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Japanese Encephalitis• Caused by Japanese encephalitis virus
• JE was first recorded in Vellore and Pondicherry in mid 1950s.
• Transmitted through zoonotic cycle b/w mosquito, pigs and water birds
• Vector- Bite of Culex tritaenniorhynchus
• Incubation Period- 6-16 days
• C/f- Fever, rigors, headache & vomiting
• Encephalitis syndrome- Difficulty of speech, ocular palsies, hemiplegia, quadriplegia, tremors, altered sensorium,convulsions, coma
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• Diagnosis- IgM – capture ELISA to detect specific IgM in the CSF or blood within 7 days of disease.
• Treatment- symptomatic & supportive
• Prevention:- Vector control by aerial or ground fogging with ultralow – volume insecticides, use of mosquito nets, locating piggeries away from human dwellings.
• JENVAC vaccine single dose for mass vaccination campaigns and also as a two-dose schedule during routine immunisation.
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Sensitivity & Specificity of the rapid IgM capture ELISA (JEV-Chex) is 100%
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Chikungunya fever• Caused by Chikungunya virus
• Transmitted by Bite of Aedes aegyptii
• C/f- Fever, chills, anorexia, conjunctivitis ,morbilliform rash on trunk and limbs, coffee colour vomiting, epistaxis, petechiae
• Prominent symptom in adults is arthropathy pain, swelling, stiffness of the metacarpophalangeal, wrist, elbow, shoulder, knee, ankle and metatarsal joints.
• Diagnosis- Detected in serum in the first 3-4 days with PCR. RT PCR to detect viral DNA.
• Treatment- Symptomatic
• Prevention- Mosquito control measures. No vaccine is available.
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LEISHMANIASIS
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Leishmaniasis
• Complex disease caused by the protozoan Leishmania
• In Indiaendemic in Bihar, Jharkhand, West Bengal and UP
• Manifests in two forms cutaneous & visceral (kala-azar) variety
• Transmitted by the bite of female phlebotomine sandfly
• C/f Fever, splenomegaly & hepatomegaly, anaemia, weight loss, darkening of skin of the face, hands, feet, abdomen and lymphadenopathy.
• Post kala-azar dermal leishmaniasis lesions develop consisting of multiple nodular infiltrations of the skin, usually without ulceration.
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• Cutaneous leishmaniasis Painful ulcers in the parts of the body exposed to sandfly bites –legs, arms or face.
• Diagnosis- Bone marrow & spleen aspirations
• Staining method most appropriate for leishmania detection is one employing panoptic May Grunwald–Giemsa stain.
• Classical blood agar NNN medium (consists of 0.6% NaCl added to a simple blood agar slope) is the most currently used media
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• Visceral leishmaniasis PCR assay is found to be almost 100% sensitive using peripheral blood
• Ultrasensitive PCR asay for visceral leishmaniasis asymptomatic carriage in man even in immunosuppressed patients.
• Other serological tests- IFAT, Immuno- enzymatic techniques, counter current immune-electrophoresis, IHA and immune blot
• Easy tests Direct Agglutination Test, rK39 immunochromatography dipstick, latex particle agglutination, dot – ELISA and fast – ELISA.
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• Treatment sodium stibogluconate (100mg/ml). Daily dose 20mg/kg iv or im for 28-30 days. Amphotericin B deoxycholate – 15 iv infusions ( dose 0.75- 1mg/kg body wt) daily or on alternate days.
• Orally administrable alkyl phospholipid, miltefosine is used. Dose 50mg BD for adults weighing 25kgand once daily for those < 25 kg, after meals for 28 days.
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TAENIASIS & CYSTICERCOSIS
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Taeniasis & Cysticercosis
• Caused by 2 parasites- Taenia saginata and Taenia solium
• Taenia solium is endemic in India & widely reported, Taenia Saginata is moderately reported.
• Transmission- Through ingestion of infective cysticerci in undercooked pork (Taenia solium ) or beef (Taenia saginata), through ingestion of food, water of vegetables contaminated with eggs.
• Cysticercosis refers to tissue infection after exposure to eggs of Taenia solium, the pork tapeworm.
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Clinical features
• Cysts are formed in the brain and muscles
• Generalised muscle pain, painful nodules in the muscles and seizures cysts in the brain
• Cysts block outflow of CSF with symptoms of sed intracranial pressure • Cysticerci in the globe, extraocular muscles, and subconjunctiva visual
difficulties that fluctuate with eye position, retinal edema, hemorrhage, a decreased vision or even a visual loss
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• Diagnosis:- Antibodies to cysticerci can be demonstrated in serum by Enzyme Linked Immunotransfer Blot assay and in CSF by ELISA
• Neuroimaging with CT or MRI is the most useful method of diagnosis.
• CT scan shows both calcified and uncalcified cysts
• Cystic lesions can show ring enhancement and focal enhancing lesions.
• MRI is more sensitive in detection of intraventricular cysts
• CSF findings include pleocytosis, elevated protein levels and depressed glucose levels
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• Prevention- Massive chemotherapy of infected individuals, improving sanitation, and educating people, cooking of pork or freezing it and inspecting meat & by treating or vaccinating pigs.
• TreatmentAlbendazole 15mg/kg body weight/ day divided in 3 oral doses for 7-28 days along with dexamtheasone.
• Praziquantel in 3 oral doses for 25 mg/kg body weight at 2 hour intervals followed by 5 hrs later by dexamthasone
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TOXOPLASMOSIS
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Toxoplasmosis• Caused by a parasite called Toxoplasma gondii
• Transmitted by infection by ingestion of tissue cysts present in raw or undercooked beef, lamb or pork and ingestion of oocysts from soil, water, milk or vegetables.
• Toxoplasmosis present worldwide with seropositivity ranging from less than 10% to over 90%.
• Seroprevalence in India is about 22% approximately
• Can be transmitted congenitally in pregnant mothers
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• Acute toxoplasmosis Swollen lymph nodes, or muscle aches and pains that last for a month or more
• Swollen lymph nodes are commonly found in the neck or under the chin, followed by the axillae (armpits) and the groin.
• Enlarged lymph nodes will resolve within one to two months in 60% of cases.
• Young children & immunocompromised peoplesevere toxoplasmosis leading to encephalitis or necrotizing retinochoroiditis
• Skin lesions roseola and erythema multiforme-like eruptions, urticaria, and maculopapular lesions
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• Laboratory diagnosis -detection of Toxoplasmaspecific antibodies done by serologic tests to detect T. gondii specific IgG, IgM, IgA or IgE antibodies.
• IFAT, LAT, DAT and ELISA are used more commonly.
• Prevention- Avoid eating raw or undercooked meat, avoid handling or
adopting stray cats. Routine antenatal screening for toxoplasmosis and treatment of infected mothers
• Treatment:- In immunocompromised pts- Pyrimethamine 200mg loading dose + 75
mg/dl+ sulphadiazine 1gm QUID or Clindamycin 600mg-1200mgQID or TMP+SMX 20mg/kg/dlin 4 divided doses+ folinic acid
In pregnancy- Spiramycin 1gm TDS
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ANTHRAX
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Anthrax• Caused by the bacterium Bacillus anthracis• Oldest recorded disease of animals
• Humans acquire infection from cattle, sheep, goats, horses and swine.• Anthrax is enzootic in southern India but is less frequent to absent in the
northern Indian states.
• Anthrax in sheep is prevalent in sheep in Andhra – TN border causing cutaneous & meningoencephalitic human infections with a high mortality rate.
• Outbreaks of Anthrax have been reported from Mysore 1999, Orissa 2004, 2005, West Bengal 2000
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• 3 clinical types of disease based on the route of infection
Cutaneous anthrax follows entry of spores through abraded skin -the typical lesions are pustules which are more commonly seen on face, neck, hands and back.
Pulmonary anthrax occurs due to inhalation of dust of wool characterized by haemorrhagic bronchopneumonia.
Intestinal anthrax is transmitted by ingestion of improperly cooked infected meat causes violent enteritis with bloody diarrhea
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• Diagnosis- Swabs, fluid or pus from pustules in cutaneous anthrax, sputum from pulmonary & blood from septicaemic anthrax patients are collected.
• Gram staining shows large gram positive bacilli.• Direct Fluorescent Antibody test for
polysaccharide cell wall antigen confirms the identification of Anthrax bacilli.
• Culture Medusa head colonies on nutrient agar and non hemolytic colonies on blood agar are seen.
• Gelatin stab culture shows inverted fir tree appearance
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• Treatment:-
Postexposure Ciprofloxacin 500 mg PO bid x 60 d or Doxycycline, 100 mg PO bid x 60 d or Amoxicillin, 500 mg PO q8h, likely to be effective if strain penicillin sensitive
Active disease Ciprofloxacin, 400 mg IV q12h or Doxycycline, 100 mg IV q12h plus Clindamycin, 900 mg IV q8h and/or rifampin, 300 mg IV q12h; switch to PO when stable. x 60 d total
Vaccines:-Licensed to prevent anthrax, it is not typically available for the general public. Anthrax Vaccine Adsorbed (AVA) protects against cutaneous and inhalation anthrax. Vaccine is approved by the Food and Drug Administration (FDA) for at-risk adults before exposure to anthrax. FDA has not approved the vaccine for use after exposure for anyone.
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THANK YOU
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