Module 5-6 Flashcards
disease that spreads easily from one host to another directly or indirectly like tuberculosis, flu, chickenpox, etc.
Communicable disease
Causal agent of cholera
Vibrio cholerae O1, Vibrio cholerae O139
cholera main mode of transmission
(oral-fecal) Drinking contaminated water - Eating food (fruits and vegetables) contaminated through: ¨ Water - Contaminated seafood - Indirect contamination (hands)
cholera incubation period
few hours to 5 days
cholera vaccine
Recently developed oral B subunit killed whole-cell (BS-WC) vaccine
diphtheria causal agent
Corynebacterium diphtheriae
diphtheria Main modes of transmission
direct contact with a patient or carrier
diphtheria Incubation period
usually 2 to 5 days but may be longer
diphtheria Prevention
Immunization: 3 doses of 0.5 ml DTP intramuscularly in outer part of thigh, according to national schedule (normally at age 6, 10, 14 weeks – if immunization is started later, there must still be an interval of 4 weeks between doses). Immunization to be completed preferably before the age of 6 months (26 weeks).
what temperature must DTP vaccine be stored at
between 2°C and +8°C
what part of the DTP vaccine are damaged by freezing
diphtheria and tetanus components
what part of the DTP vaccine are damaged by heating
pertussis
Japanese Encephalitis causal agent
Japanese encephalitis virus, of the family Flavivirus
Japanese Encephalitis main mode of transmission
(vector) Bloodsucking Culex mosquitoes (mainly Culex tritaeniorhynchus, Cx. gelidus and Cx. fuscocephala) transfer the virus to humans from infected animals, in most cases domestic pigs and wading birds. Human beings are not considered a reservoir for viral transmission. In most areas transmission starts in April or May and lasts until September or October. Where irrigation permits mosquito breeding throughout the year, transmission may occur even in the dry season
Japanese Encephalitis incubation period
1 to 2 weeks
Haemophilus Influenzae Type B causal agent
Haemophilus influenzae type b is one of 6 types (a, b, c, d, e, f) Type b bacteria account for 95% of serious H. influenzae infections in children. H. influenzae strains live in the nose and throat of people and usually do not cause serious illness.
Haemophilus Influenzae Type B main mode of transmission
(droplet spread) Hib bacteria may spread throughout the body and become life- threatening (mostly in children under 5 years) - Hib bacteria pass from child to child in droplets of saliva when an infected child coughs or sneezes, and also when children share things they have put in their mouths. Hib disease is most common in children under 5 years, and children between the ages of 4 and 12 months are at highest risk. By 4 to 5 years of age, children develop their own immunity; Hib disease rarely occurs after that age.
Haemophilus Influenzae Type B immunization
Three doses of 0.5 ml at monthly intervals, starting at 6 weeks or later (6, 10, 14 weeks), together with DTP, OPV, HepB (intramuscular administration in thigh or arm, not in the buttocks).
all children must receive how many doses of Hib vaccine
3 doses in their first year, beginning after 6 weeks of age
Hepatitis A causal agent
Positive-strand RNA virus (Picornavirus)
Hepatitis A main mode of transmission
faecal-oral; in practice, the reservoir is exclusively human. The agent of hepatitis A occurs in faeces, at peak levels in the week preceding the onset of symptoms and diminishing rapidly after symptoms appear.
Hepatitis A vaccine
good Hepatitis A vaccine, Immunoglobulin (0.02 ml/kg body weight IM) is reserved for special urgent cases.
Hepatitis B causal agent
Hepadnavirus (Hepatitis B)
Hepatitis B main mode of transmission
Percutaneous or permucosal exposure to blood or other infectious body fluids. It is found in highest concentrations in blood and serous exudates; lower concentrations are found in other body secretions, including saliva, semen and vaginal fluid. HBV is stable on environmental surfaces for at least 7 days. Reservoir is man.
Major modes of HBV transmission: sexual contact with an infected person, perinatal transmission shared needles among injecting drug users, household contact and blood transfusions.
Hepatitis B vaccine/immunization
Postexposure immunization beginning at birth is highly effective in preventing neonatal infections in infants of HBVinfected mothers. Optimum efficacy is achieved when vaccine is administered within 24 hours (preferably 12 hours) after birth. A total of 3 doses must be given (second and third doses at 1 and 6 months.
Leprosy causal agent
Mycobacterium leprae.
Leprosy main mode of transmission
(direct contact) Humans are the only significant reservoirs. Transmission is direct contact. Can survive up to 7 days in dried nasal secretions.
Leprosy prevention/vaccine
BCG vaccination - Dapsone chemoprophylaxis is not recommended (limited effectiveness and danger of resistance)
malaria causal agent
Plasmodium (P. falciparum, P. vivax, P. malariae, P. ovale). P falciparum, the most prevalent species, is responsible for the majority of malaria deaths.
malaria main mode of transmission
(vector) blood of an infected person, parasites enter the female blood- sucking anopheline mosquito, develop in the gut and lodge in the salivary glands. When the infective mosquito takes a new blood meal, parasites are transmitted and carried by the blood to the liver where they multiply. This induces bouts of fever and severe anaemia.
malaria incubation period
1 to 4 weeks for P. malariae, 1 to 2 weeks for others M
malaria prevention/vaccine
Personal protection and vector control measures: Insecticide-treated bednets and other materials (ITMs) have proven highly efficacious in reducing morbidity and mortality in areas of high, moderate and low malaria transmission in Africa.
measles causal agent
Measles virus of the genus Morbillivirus, family Paramyxoviridae
measles main mode of transmission
airborne droplets, direct contact with nasal or throat secretions
measles prevention
Single dose of live attenuated measles vaccine after 9 months of age. Second dose may increase immunity levels to as high as 99%. Measles vaccine is effective and safe and it can be combined with other live vaccines. The main reason for the persistence of the disease burden is underutilization of the vaccine.
measles incubation period
(to onset of fever or rash): 7 to 18 days
meningococcal disease causal agent
Neisseria meningitidis
meningococcal disease main mode of transmission
aerosol or direct contact with the respiratory secretions of infected persons (including symptomless carriers)
meningococcal disease incubation period2 to 10 days.
2 to 10 days
meningococcal disease prevention
Chemoprophylaxis may be considered for close contacts (rifampicin, ciprofloxacin, ceftriaxone or other as advised by the health authorities – but not penicillin or chloramphenicol)
meningococcal disease vaccination
for close contacts (A, C, Y, or W135 serogroups) to prevent secondary spread. Polysaccharide vaccines are available against serogroups A, C, Y, W135
pertussis causal agent
Bordetella pertussis
pertussis main mode of transmission
airborne route. Humans are the only hosts
pertussis prevention
use of whole-cell vaccine against pertussis (wP) has been effective in preventing pertussis. The vaccine should be given in 3 doses at 4-week intervals starting at the age of about 6 weeks
pertussis incubation period
7 to 10 days and rarely more than 14 days
poliomyelitis causal agent
Poliovirus (Enterovirus) types 1, 2 or 3
poliomyelitis incubation period
7 to 14 days
poliomyelitis prevention immunization
Oral poliovirus vaccine (OPV). OPV is a live vaccine including live attenuated strains of all three virus types. OPV is the only vaccine of choice for poliomyelitis eradication because it achieves much better mucosal immunity than IPV.
Basic immunization at birth, 6, 10 and 14 weeks
poliomyelitis main mode of transmission
faecal-oral
rabies causal agent
The rabies virus, a Rhabdovirus of the genus Lyssavirus.
rabies main mode of transmission
Hosts are usually Canidae, including dogs (responsible for more than 99% of all human deaths from rabies), foxes, coyotes, wolves, and jackals; also cats, skunks, raccoons, mongooses, bats, and other biting animals. A bite or a scratch introduces virus-laden saliva from a rabid animal.
rabies incubation period
2 to 10 days but may be longer (up to 7 years)
rabies vaccine
potency at least 2.5 IU per dose according to one of the following schedules. - Intramuscular schedules: volume of 1 dose; 1 dose on days 0, 3, 7, 14 and 28. All intramuscular injections to be given into deltoid region or into anterolateral area of the thigh muscle in small children. Never inject the vaccine in the gluteal region.
rubella causal agent
Rubella virus, of the genus Rubivirus of the family Togaviridae
rubella main mode of transmission
droplets in the air from the nose and pharynx of infected people, or by direct contact with nasal or pharyngeal secretions
rubella prevention
Monovalent rubella vaccine - Measles and rubella vaccine (MR) - Measles, mumps and rubella vaccine (MMR)
second highest prevalence for tropical diseases (following malaria) and is a leading cause of severe morbidity in large parts of Africa, Asia and the Americas
Schistosomiasis
Schistosomiasis causal agent
Fluke worms: - Schistosoma haematobium, agent of urinary schistosomiasis worldwide - Schistosoma mansoni, agent of intestinal schistosomiasis worldwide - Schistosoma japonicum, agent of intestinal schistosomiasis endemic in China, Indonesia, Philippines - Schistosoma mekongi, agent of intestinal schistosomiasis encountered in Cambodia and Laos
Schistosomiasis main mode of transmission
The eggs of schistosomes leave the human body in urine or faeces according to species, hatch in water and liberate larvae (miracidia) that penetrate into freshwater snail hosts (genus Biomphalaria for S. mansoni, Bulinus for S. haematobium and S. intercalatum, Oncomelania for S. japonicum, and Neotricula for S. mekongi). After several weeks, cercariae emerge from the snails and penetrate the human skin (during wading, swimming, washing). Human discharge of eggs may last in excess of 10 years.
Schistosomiasis interventions
Praziquantel is the drug of choice against all schistosome parasites. A single oral dose of 40 mg/kg is generally sufficient to give cure rates of between 80% and 90%.
Schistosomiasis prevention
Creation of alternative, safe water sources to reduce infective water contact - Proper disposal of faeces and urine to prevent viable eggs from reaching bodies of water containing snail hosts - Treatment of snail-breeding sites with molluscicides.
tetanus causal agent
Clostridium tetani
tetanus main mode of transmission
Spore-carrying instruments (use of unsterile tools) - Dirty hands - Spore-carrying material covering the umbilicus (e.g. dung poultices)
tetanus prevention
The most effective strategy is the immunization of pregnant women at risk.
tuberculosis causal agent
Mycobacterium tuberculosis
tuberculosis main mode of transmission
Airborne
tuberculosis incubation period
Primary infection, may occur 2 to 10 weeks after. Bacilli may remain latent for many years or a lifetime and may produce late disease when the immune status of the patient deteriorates (through age or associated factors).
tuberculosis prevention
BCG vaccination. Chemoprophylaxis of infected individuals with isoniazid for 6 months reduces the risk of disease by 80-90%. Alternative to isoniazid is to give rifampicin/pyrazinamide for 2 months. Environmental protection: air renewal (outside ventilation); sunlight and UV light kill the infectious agent
typhoid fever causal agent
Typhoid fever: Salmonella typhi (new nomenclature: Salmonella enterica serovar Typhi)
typhoid fever main mode of transmission
(fecal-oral) Ingestion of food and water contaminated by faeces and urine of patients and carriers. Faecal carriers occur in about 2% of infected adults. Chronic carriers are most common among persons infected at an older age, especially women and often in patients with biliary tract abnormalities.
typhoid fever prevention
Early isolation and typing of the causal agent in order to identify the source of the outbreak and facilitate control - Safe food-handling - Personal hygiene including hand-washing.
Antibiotherapy (chloramphenicol, ampicilline, ciprofloxacine or trimethoprim-sulfamethoxazol TMP- SMX) must be offered to all patients.
mosquito-borne viral haemorrhagic fever that strikes over 200 000 people and causes over 30 000 deaths each year in tropical regions of Africa and South America; it is maintained by sylvatic transmission of virus involving forest-dwelling mosquitoes and monkeys. Transmission to humans may occur in forest transition zones.
yellow fever
yellow fever causal agent
arthropod-borne Flavivirus
yellow fever main mode of transmission
(vector) species of Aedes or Haemagogus mosquitoes. Humans and monkeys are the main species to be infected. The mosquito is thus the true reservoir of the virus, ensuring transmission from one year to the next.
yellow fever incubation period
3 to 6 days
yellow fever prevention
Vaccination: most important measure for preventing yellow fever. Current yellow fever vaccines have a shelf-life of up to 2 years at a temperature of –20°C or +4°C; Eliminating potential mosquito breeding sites
:transmitted by ingestion of contaminated water
Waterborne diseases
transmitted by the ingestion of contaminated food
Foodborne diseases
transmitted through the air
Airborne diseases
transmitted by vectors, such as mosquitoes and flies
Vector-borne diseases
Three Levels of communicable disease prevention:
Public health measures
Personal hygiene
Vaccination programs
Major cause of illness and death in poor
countries.
Communicable Diseases
Describes the pattern by which an
infectious disease is transmitted from
person-to-person.
A continuous link of 6 components
Chain of Infection
Infection that is constantly present in a given geographical area
Endemic
Infection wherein the incidence is greater that what would be expected
Outbreak
Occurence of disease at higher than expected levels in a particular region or area
Epidemic
Infection that rapidly spreads in most parts of the world
Pandemic
rice water stool
Diarrhea
Hansen’s Disease
Leprosy
Whooping cough
Pertussis
lockjaw
Tetanus
Anthrax
Bacillus anthracis
Anthrax
Direct contact with infected animal tissue or products (wool, hair)
Inhalation of spores
Ingestion of contaminated meat
Woolsorter’s Disease
Pulmonary Anthrax
Intestinal worms infecting humans that are
transmitted through contaminated soil
Soil-Transmitted Helminthiasis (STH)
Soil-Transmitted Helminthiasis (STH) causative agent
○ Ascaris lumbricoides (Giant Intestinal Worm)
○ Trichuris trichiura (Whipworm)
○ Hookworms (Necator americanus, Ancylostoma
duodenale)
STH Mode of transmission
Ingestion of egg (from contaminated water or vegetations
on the soil)
The key intervention for
the control and
prevention of STH
infections
WASHED Framework
Second leading cause of permanent and long-
term disability
Lymphatic Filariasis
Lymphatic Filariasis
○ Wuchereria bancrofti
○ Brugia malayi
The fastest spreading vector-borne disease in the world endemic in 100
countries
Dengue
Dengue Mode of transmission
○ Aedes aegypti
○ Aedes albopictus
HIV/AIDS causative agent
Human Immunodeficiency Virus
○ HIV 1 (worldwide)
○ HIV 2 (West Africa)
HIV/AIDS Mode of transmission
○ Sexual, Vertical, Bloodborne, Breastmilk
○ Needle-stick injury
○ Sharing of contaminated needles among IV drug users
Pathology of HIV/AIDS
Stage 1 – Acute HIV infection
Stage 2 – Chronic HIV infection
Stage 3 - AIDS
A disease caused by the novel coronavirus
first reported from Wuhan, China in
December 2019
COVID-19
COVID-19 Causative Agent
SARS-CoV-2
COVID Mode of transmission
○ Inhaling droplets in air when in close contact with
infected person
○ Exposure to small droplets through splashes like
cough or sneeze
○ Touching eyes, nose, or mouth with hands that
have virus on them
● aka Chronic Disease
● Chronic condition that does not result from an infectious process
● A disease that has prolonged course, that does not resolve spontaneously,
and for which a complete cure is rarely achieved.
Noncommunicable Diseases (NCD)
Characteristic of NCD
● Complex etiology
● Multiple risk factors
● Long latency period
● Non-contagious origin
● Prolonged course of illness
● Functional impairment or disability
An aspect of personal behavior or
lifestyle, an environmental exposure,
or a hereditary characteristic that is
associated with an increase in the
occurrence of a particular disease,
injury, or other health condition
Risk Factors
A behavioral risk factor that can be reduced or controlled by intervention, thereby reducing the
probability of disease.
Modifiable Risk Factor
Physical inactivity, tobacco use, alcohol use, and unhealthy
diet
Prioritized Risk Factors (WHO)
○ A risk that cannot be reduced or controlled by intervention
○ Age, Sex, Race, and Family History
Non-modifiable Risk Factor
Behaviors that can lead to metabolic/physiologic changes
Metabolic Risk Factor
refers to the biochemical processes involved in the body’s normal functioning
Metabolic
Raised Blood Pressure, Raised Total Cholesterol, Elevated
Glucose, Overweight and Obesity
Prioritized Risk Factors (WHO)
TARGET: Entire population
EFFECTS: Prevent risk factors, lower
population risk
HEALTH PROMOTION
TARGET: People with one or more risk
factors
EFFECTS: Prevent development of
disease at early age
PRIMARY INTERVENTION
TARGET: People at early stage of
disease
EFFECTS: Prevent disease progression or
recurrence
SECONDARY
INTERVENTION
TARGET: People with symptomatic or
advanced disease
EFFECTS: Reduce complication or
disability
TERTIARY INTERVENTION
Four main NCDs
Cardiovascular Disease (CVD)
Diabetes Mellitus
Cancer
Chronic Respiratory Diseases
a group of disorders of the heart and blood vessels
#1 cause of death globally
Cardiovascular Disease (CVD)
Disease of the blood
vessels supplying heart
muscles
Coronary Heart Disease
(CHD)
Disease of the blood
vessels supplying the brain
Cerebrovascular Disease
(Stroke)
Disease of the blood
vessels supplying arms
and legs
Peripheral Arterial
Disease
Malformation of heart
structure existing at birth
Congenital Heart Disease
Disorder of metabolism
Defect in insulin secretion, insulin action
Diabetes Mellitus
4 types of Diabetes
● Type I
● Type II
● Gestational DM
● Pre-diabetes (Impaired Glucose Tolerance)
Hyperglycemia as a result
of an individual’s
resistance to insulin with
an insulin secretory defect
DM Type II
The most common type of
DM worldwide (>90% of
total diabetes cases)
DM Type II
● Rapid creation of abnormal cells that grow beyond their usual boundaries,
and which can then invade adjoining parts of the body and spread to other
organs - WHO (2012)
● Generic term for a large group of diseases that can affect any part of the
body.
● Autonomous growth of cells that often forms a solid mass (tumor) and
spreads to other areas of the body
Cancer
○ Tumor that remains localized (does not invade
surrounding tissues)
○ Nomenclature: cell type + ‘’oma”
BENIGN
○ Tumor that may invade and destroy adjacent cells
(metastasis)
MALIGNANT
Cancer of female reproductive system
Cervical Cancer
Cancer that forms in tissues of the lung, usually in the cells lining air passage
Lung Cancer
Leading cause of cancer death globally (1.37 million death in 2008)
Lung Cancer
Cancer that forms in the tissues of the breast (ducts or lobules)
Breast Cancer
2nd most common cancer among men
Prostate Cancer
3rd most common type of cancer
Colorectal Cancer
90% of deaths occur in low-income
countries
Chronic Respiratory Diseases
term used for lung diseases that prevent
proper lung airflow
Chronic Obstructive Pulmonary Disease
(COPD)
Recurrent attacks of “breathlessness and wheezing.
Asthma
procedure of killing most, but not all, infectious agents outside the body by direct exposure to chemicals
Disinfection
involves destruction of all forms of micro-organisms by physical heat, irradiation, gas or chemical treatment.
Sterilisation
procedure of destroying or removing small animal pests, particularly arthropods and rodents, present upon the person, the clothing, or in the environment of an individual, or on domestic animals.
Disinfestation
Enhanced 4S Strategy
S-earch and Destroy
S-eek early consultation
S-elf protection measures
S-ay yes to fogging only during outbreaks
provides for immunization against Hepatitis B in addition to the common vaccine-preventable diseases.
A. 10152 (Mandatory Infants and Children Health Immunization Act of 2011)
Six WHO Objectives for Non-Communicable Diseases
Priority: Raise priority and integrate prevention and control into policies
Leadership: Establish and strengthen national policies and plans
Interventions: Focus on shared modifiable risk factors
Research: Promote research for NCD prevention and control
Partnerships: Promote partnerships for NCD prevention and control
Monitor and Evaluate: Monitor NCDs and determinants and evaluate progress
