Rabies and TB

DISEASE CONTROL- PRINCIPLES AND STRATEGY, METHODS OF CONTROL

FOR SELECTED DISEASES

Selected Diseases

• Malaria

• Guinea Worm

• STDS/HIV-AIDS

• Onchocerciasis

• Tuberculosis

• Rabies

• Anthrax

Rabies

Outline

• Background on Rabies – Virology

– Mode of transmission

– Clinical presentation

– Outcome

• Rabies as a zoonotic

• Public health importance

• Prevention and control

• Pre- and Post-exposure Prophylaxis

Background

• Rabies is a zoonosis caused by the Rabies virus an RNA viruses belonging to the genus Lyssavirus, in the Rhabdoviridae

• It is a disease of the nervous system

• It is transmitted via secretions (oral and nasal) of infected animals to others and humans through bites, licks, exposure to nasal and oral discharges

• Other forms of transmission as aerosol debatable

Background

• Diagnosis is usually clinical and at post-mortem, the identification of Negri bodies in neural tissue

• Two epidemiological forms of rabies: – Urban Rabies in domestic dogs

– Wildlife rabies in wild animals like foxes, bats etc

• Rabies presents in two clinical forms – Dumb (paralytic) rabies

– Furious rabies

Epidemiology

• Worldwide distribution except in Antartica

• Rabies occurs in more than 150 countries and territories

• > 55 000 deaths per year mostly in Asia and Africa

• 40% of persons bitten by suspect rabid animals are children <15 years of age

• Dogs account for majority of human rabies deaths

Epidemiology

• Dogs account for majority of human rabies deaths

• >15 million persons receive post-exposure vaccination annually

• 6 cases reported by Ghana Health Service Facilities

• KATH has recorded 2 deaths from Rabies so far this year

Public Health importance

• Vaccine preventable illness (Vaccine available and cheap at veterinary services

• Near absolute case fatality rate

• Animal reservoirs including wild animals as bats, foxes etc

• Immunoglobulin very expensive and scarce

Surveillance for Rabies • One of the priority diseases under surveillance

in Ghana

• A case of Human Rabies is to be reported immediately to the Disease Surveillance Department of the Ghana Health Service

• Case Definition (Suspected case) : A person with one or more of the following: headache, neck pain, nausea, fever, fear of water, anxiety, agitation, abnormal tingling sensations or pain at wound site, when contact with a rabid animal is suspected

Prevention and Control

• Vaccination

– Vaccination of domestic animals at least once every 3 years

– Vaccination of contacts with rabid animals

– Vaccination of persons most at risk e.g. Vets

– ?Vaccination of wild animals

• Legislation and enforcement

– Control of stray animals especially dogs

– ?compulsory vaccination of pets


• Control of animal reservoirs

– Elimination of stray animals

– Identification and destruction of infected animals

– Observation or destruction of animal contacts of a rabid dog

• Surveillance

– Prompt detection and reporting

– Prompt institution of control measures

Post-exposure Prophylaxis • Involves active and/or passive immunisation

following exposure to a rabid animal

• Depends on the following

– Prevalence of rabies in area

– State of health of animal

– Site of bite (head, neck, face, hands carry higher risk)

– Extent of bite (multiple or deep wounds)

Post-exposure Prophylaxis

• Usually Human Rabies Immunoglobulin (single dose) in combination with Rabies vaccine (Vaccine given at days 0,3,7,14 and 21

• Wound cleansing and immunization within a few hours after contact with a suspect rabid animal can prevent the onset of rabies and death

Pre-exposure vaccination

• To persons at risk of exposure to rabies e.g. Veterinary workers

• 4 doses of Rabies vaccine at days 0, 7, 14 and 21

Tuberculosis

Outline

• Background – Causative agents

– Risk factors

– Mode of transmission

– Clinical presentation

– Treatment and complications

• Epidemiology and Public Health Importance

• Surveillance for TB

• Prevention and control of TB

Background

• An infection caused by acid-fast baccili (mycobacterium)

• Mycobacterium tuberculosis is the commonest

• Others include M bovis, M microti and M africanum

• Mode of transmission via droplet nuclei from sneezing, coughing etc

• Other modes of transmission as unpasteurised milk (M bovis) documented

Risk factors for TB

• HIV or AIDS

• One or more of the following medical conditions: – Diabetes mellitus

– Renal failure and those on chronic haemodialysis

– Immunosuppressive therapy

– Intestinal bypass or gastrectomy

• Previous history of TB infection (including complete, incomplete or failed treatment)

• Overcrowding

• Malnutrition

Clinical presentation

• Patients also have systemic symptoms such as chills, night sweats, fever, easy fatigue, loss of appetite, and/or weight loss

• Cough usually of a week or more in duration

• Other symptoms in relation to the organ or body part affected (Brain- TB Meningitis, Bone- Pott’s Disease; Lymph nodes- TB Lymphadenitis)

Treatment

• Based on national guidelines provided by the National TB Control Programme

Epidemiology

• An estimated 8.7 million incident cases of TB in 2011 (13% co-infected with HIV)

• 1.4 million deaths from TB (990 000 deaths among HIV-negative individuals and 430 000 among people who were HIV-positive)

• 0.5 million among women making TB one of the top killers of women worldwide

Estimated Global TB Incidence 2011

Estimated Global HIV Prevalence in net TB cases

Epidemiology- Ghana

• Cases of Bovine TB increased from 88 in 2009 to 106 cases in 2010 in Ghana

• The majority of TB cases are among males

• HIV infection among TB patients estimated to be around 30 to 50%

• TB infection among HIV positive persons about 15%

Public Health Importance

• Increasing incidence of infection as a result of HIV infection

• Multi-drug resistant strains of mycobacterium

• Global objective of reducing cases of TB (United Nation’s MDGs)

• Mode of transmission

• Increasing numbers of aged people

• Increasing numbers of persons with diseases associated with reduced immunity as Diabetes

Surveillance for TB

• TB is one of the diseases under surveillance in Ghana

• It is regarded as a disease of Public health importance hence its inclusion

• Case definition (Suspected case): Any person with a cough of two weeks duration or more; in an HIV positive person, a cough of any duration


• Vaccination using the bacillus Calmette-Guérin (BCG) vaccine- a live attenuated vaccine

• Cough etiquette

• Screening of at-risk persons and prompt treatment

• Pasteurisation of milk

• Elimination of infected cattle

Objectives of the National TB Control Programme

• Pursue high-quality DOTS expansion and enhancement – Political commitment with increased and

sustained financing

– Case detection through quality-assured bacteriology

– Standardized treatment, with supervision and patient support

– An effective drug supply and management system

– Monitoring and evaluation system, and impact measurement


• Address TB/HIV, MDR-TB and other challenges

– Implement collaborative TB/HIV activities

– Prevent and control MDR-TB

– Address prisoners, refugees and other high-risk groups and situations


• Contribute to health system strengthening

– Actively participate in efforts to improve system-wide policy, human resources, financing, management, service delivery, and information systems

– Share innovations that strengthen systems, including the Practical Approach to Lung Health (PAL)

– Adapt innovations from other fields


• Engage all care providers – Public–Public and Public–Private mix (PPM)

approaches – International Standards for Tuberculosis Care (ISTC)

• Empower people with TB, and communities – Advocacy, communication and social mobilization – Community participation in TB care – Patients’ Charter for Tuberculosis Care

• Enable and promote research – Programme-based operational research – Research to develop new diagnostics, drugs and

vaccines

Reading Assignment

• Malaria

• Guinea Worm

• STDS/HIV-AIDS

• Onchocerciasis

• Anthrax

Rabies and TB

Documents