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.