Viral Infection Diagnosis and Symptoms Quiz

Yellow Fever

• A communicable arthropod-borne viral hemorrhagic quarantinable acute disease of short duration & varying severity.
• Causative agent: Yellow fever virus.

Objectives (Learning outcomes)

• Definition
• Mode of transmission
• Manifestation
• Prevention &control

How Egypt is protected from Yellow Fever

• Absence of yellow fever in Egypt & its rarity in other areas, such as Eastern Africa, despite wide spread of vector aedes Egypti may be due to cross immunity from other flavi virus (e.g. dengue, west Nile, Japanese encephalitis) in population which may be providing an (ecological barrier).

Reservoir

• Sylvatic or Jungle yellow fever: main reservoir in forest area is vertebrates other than human mainly monkeys & vector is forest mosquitoes (haemagogus species).
• Human has no essential role in transmission of yellow fever. Sylvatic is a scientific term referring to diseases or pathogens affecting only wild (sylvan means forest-dwelling) animals.
• Urban yellow fever: reservoir is human & vector is Aedes aegypti mosquitoes.

Period of communicability

• No man-to-man transmission.
• Blood of man is infective to mosquito shortly during late IP & during first 3-5 days of disease.
• In mosquitoes after biting an infected person there is 9-12 days extrinsic IP, then the mosquito becomes infective all over its life.
• There is also trans-ovarian transmission which may contribute to maintenance of infection.

Mode of transmission

• Urban yellow fever: bite of infective female Aedes aegypti mosquitoes.
• Sylvatic or jungle yellow fever: bite of several species of genus Haemagogus.
• IP: 3-10 days (6 days in international health regulation).

Susceptibility & resistance

• Age & sex: all ages & both sexes are susceptible.
• Immunity: infection is followed by absolute immunity, 2nd attacks are unknown.
• Transient passive immunity to inborn infant of immune mother occurs for up to 6 ms.
• Occupation: Woodcutter, Hunter.

Clinical features

• Mild form: sudden onset, fever, headache, maliase and anorexia (FHMA), chills, muscle pain, prostration, nausea & vomiting.
• Faget sign: slow pulse out of proportion of elevated temperature.
• Jaundice is moderate early in disease & intensified later.
• Albuminuria or anuria may occur, leucopenia.
• Most of the manifestations resolve after 5-7 days.
• After a brief remission of hours to a day some cases progress to severe form (hemorrhagic symptoms including epistaxis, gingival bleeding, haematemesis (coffee ground or black) melena, liver & renal failure).
• Fatality rate of jaundiced cases may reach 20-50%.

Diagnosis

• Isolation of virus from blood by inoculation of suckling mice, mosquito or cell culture.
• ELISA “viral antigen in blood".
• PCR "viral genome in blood & liver tissue".
• Serologic diagnosis "specific IgM in early sera or rise in titer of specific antibodies".

Prevention

• General:
• Environmental sanitation.
• Eradication or control of Aedes Aegypti:
  • Anti-larval
  • Anti-adult measures
• Jungle mosquitoes “impractical”.
• Human protection against mosquitoes: e.g. protective clothing, bed nets, repellents.
• Health education: modes of transmission.

Specific

• Immunization: - Active Immunization: “most effective preventive measure” - 17 D vaccine: - Live attenuated vaccine "non virulent strain cultivated on chick embryo & subsequently freeze dried". Vaccine is stored at -25°C. - Single dose, 0.5ml, S.C. injection. - 99% immunity: - International health regulation considered vaccine effectiveness to start after 10days & persists for 10 years & then re-immunization is required. - No or minimal reaction “1st 4 ms of life....vaccine associated encephalitis".
• Given to:
  • International travelers coming from or going to endemic countries
  • Since 1989 WHO has recommended that at risk countries in Africa that fall in the endemic belt should incorporate it into their routine childhood immunization program after 6 month.

Valid vaccination certificate

• Is required from all international travelers including children coming from or going to endemic areas "Yellow Fever belt".
• Validity starts 10 days after primo-vaccination & lasts for 10 ys.
• Validity starts on same day after re-vaccination & lasts for 10 ys. If no certificate is available: traveler is isolated for 6 days from date of leaving endemic area.
• If traveler arrives before 10 days of vaccination, i.e. certificate is not valid yet: traveler is isolated until certificate becomes valid or until end of international IP calculated from day of leaving last endemic area.
• Traveler is quarantined in mosquito-proof accommodation in airport.
• This certificate is required by many countries including Egypt.

International measures

• one of quarantinable diseases & following measures should be done to prevent introduction of yellow fever from endemic area (Yellow Fever belt) into receptive area (areas free of yellow fever, but the vector is present & population is susceptible e.g. in Egypt):
• Notification within 24 hs by governments to WHO.
• Disinfection of any aircraft leaving an endemic area for receptive area, by aerosol spray of suitable insecticide, shortly before departure and also on arrival.
• Quarantine of imported monkeys.

Non-communicable diseases

• Non-communicable diseases are usually chronic conditions that do not result from an infectious process.
• These diseases are not transmitted from person to person and may cause death, dysfunction, or impairment in the quality of life, and they usually develop over relatively long periods.

Characteristics of Non-Communicable Diseases

• Non-contagious origin
• Multiple risk factors
• Long latency period
• Prolonged course of illness
• Functional impairment or disability
• Examples: cardiovascular diseases, tumors, endocrinal diseases, accidents, & nutritional deficiency diseases

Risk Factors Associated with Non-Communicable Diseases

• Tobacco use
• Physical inactivity
• Overweight/obesity
• High blood pressure
• High cholesterol levels
• High blood glucose levels

Reasons for Increase of Non-Communicable Diseases in Egypt

• Increased life expectancy
• Increase in traffic injuries
• Lifestyle changes (smoking and cancer)
• Physical inactivity (sedentary life, obesity)
• Social and behavioral factors
• Cultural factors (noise and overcrowding)

Hypertension

• A disease of high blood pressure above the average for age and sex for an adult at rest.
• It should and must be accurately estimated repeatedly to be sure that it is pathological
• Persistent hypertension can develop in response to an increase in cardiac output or a rise in peripheral resistance
• Defects may be present in one or more of the factors that affect both the cardiac output and peripheral resistance
• Prehypertension: not a disease or hypertension, not an indication for drug treatment or have a BP goal, but the status of a person does predict a higher risk for CV events & developing HTN, so it should be an incentive to improve lifestyle practices for prevention of HTN and CVD.

Risk factors in essential hypertension

• Genetic
• Low birth weight (LBW)
• Sodium salt intake
• Obesity
• Decreased physical activity
• Alcoholic beverages
• Smoking
• Hyperuricemia
• Ethnic group, i.e. adult blacks more frequently
• Sex, before menopause hypertension is less common in women
• Age
• Diabetes Mellitus
• Environmental factors
• Tension & anxiety
• Stress

Secondary Hypertension

• There are pathological conditions:
  • Renal causes
  • Endocrine causes
  • Exogenous hormone and drugs
    • Estrogen
    • Glucocorticoids
    • Mineralocorticoids
  • Coarctation of the orta
  • Eclampsia
  • Acute stress (Surgery and Hypoglycemia)

Symptoms of hypertension

• Asymptomatic
• Headache
• Tinnitus
• Dizziness
• Fainting

Prevention of hypertension

• Primary prevention:.
  • Weight reduction
  • Tobacco avoidance
  • Dietary sodium restriction
  • Potassium supplementation
  • Prevent or limit alcohol intake
  • Relaxation exercise.
  • Health education of the high risk individuals to undergo periodic medical tests screening and management
• Secondary Prevention:.
  • Control the underlying cause
  • Anti-hypertensive therapy
  • Prevention and control of hypertensive heart disease
  • Early diagnosis and proper medical control
  • Early detection and preventive treatment for renal affection
• Tertiary prevention:
  • Rehabilitation of cases of complicated hypertension.

Ischemic Heart Disease

• Epidemiological characteristics: usually above 40 years of age, more common in males than females with ratio 4:1 below 60 years of age (this may be of estrogen protection)
• This ratio may differ after menopause when estrogen decline and serum level of High density lipoprotein (HDL) declines and total serum cholesterol increases which predispose to heart attack
• Risk factors
  • Smoking: the relative risk is 3 times in those who smoke more than 20 cigarettes/day.
  • Socioeconomic level: It is more among high social level may be due to sedentary life styles, ↑ mental activity and smoking habits, stress, obesity hyperlipidemia
  • Occupation: It affects more those occupations, with sedentary life than those with heavy physical effort
  • Hyperlipidemia, as hypertension, diabetes, renal insufficiency, C.H.D
  • Alcohol consumption
• Clinical profile: May be asymptomatic, Angina pectoris (chest pain, discomfort vary in grades and shape occurs through effort and relieved by rest usually retrosternal and a referral to the left shoulder, accompanied by nausea and possible vomiting.

Management of Ischemic Heart Disease

• Prevention of smoking.
• Avoid sedentary life and mental stress.
• Proper control of diabetes mellitus.
• Health education of the population on early signs of CHD.

Malaria

• Causative agent: protozoan parasites with asexual & sexual phase “Plasmodium vivax, P. falciparum, P. ovale & P. malaria.

• Mixed infections are not frequent in endemic areas.

• Reservoir: Humans are the most important reservoir of human malaria. A case may have several plasmodia species at the same.

  • The infective stage to vector is gametocytes which have to be mature, both sexes, sufficient density & viable.
  • Antimalarial drugs lose viability of gametocytes.
  • Female anopheline mosquito is definitive host
  • Infective stage to man is sporozoite..

• Humans may infect mosquitoes as long as infective gametocytes are present in the blood, this varies with parasite species and with response to therapy.

• Untreated or insufficiently treated patients may be a source of mosquito infection for 1 to several years.

• Transfusion transmission may occur as long as asexual forms remain in the circulating blood-Stored blood can remain infective for at least a month

• Mode of transmission 1- Bite of infective female anophiline mosquito, where sporozoite are present in salivary glands.Most species feed at night; some important vectors also bite at dusk or in the early morning 2- Infection or transfusion of infected blood, or use of contaminated needles & syringes (e.g. injecting drug users) may also transmit malaria. 3- Congenital transmission occurs rarely. However, pregnant women are more vulnerable than others to falciparum malaria (and possibly other plasmodium species).

• Incubation period: - Time between infective bite & appearance of clinical symptoms is 9-40 days according to type of malaria species - with infection through blood transfusion, IP depend on the number of parasites infused & are usually short, but may range up to about 2 months.

• Malaria Survey is a Field study in endemic areas to find out the the magnitude of the problem, ecological factors & to plan for prevention and control. a)Planning: -Mapping area to identify water channels, collections, cultivated lands, houses & climatic conditions. -Study population characteristics e.g.: age, sex, occupation, habits -Study vector -Mosquito species, density, life span, breeding places, insecticides sensitivity levels. -Choose the suitable representative

• Clinical picture: slowly rising fever, chills, malaise, headache, nausea, lassitude, muscle & joint pain, then rigor sensation & rapidly rising temperature ending by profuse sweating.

  • cycle of fever, chills, sweating is repeated either daily or every other day or every third day or irregularly according to malaria species with relapses that may occur after a period of cure without parasitaemia at irregular interval up to 5 years

• Susceptibility It is universal except Genetic

• Genetic Most indigenous populations of Africa show a natural resistance to infection P vivax which is associated with absence of Duffy factor on their erythrocytes

• Persons with sickle cell trait show relatively low parasitaemia when infected with so relatively protected severe disease; homozygote's suffering from sickle cell disease at increased risk of severe falciparum malaria especially anemia

Complications and Diagnosis

• Symptoms of malaria: fever, headache, chills.
• Diagnosis: malaria parasites in thick blood film.
• Prevention:
  • General preventive measures for arthropod borne diseases, and environmental sanitation.
  • vector control and Health education like *Elimination the sites *Eradication of larval stages by spraying stages by crude oil & water surface and destruction with insecticides

Viral hepatitis B and hepatitis C

• Epidemiolgy: a worldwide distribution
• Transmission-1: hepatitis C mainly and primarily by blood-to-blood contact in countries where sharing IV drug equipment is most common Also, ear piercing & body piercing (non-sterile equipment), tattoos, prevalent rate by injectable use and for use.
• Transmission -2 HCW handling blood risk,
  • The communicability occurs during acute stage and is indefinite with individuals. The risk is minimal or non-existent for individuals
• Clinical feature test:
  • ranges and occurs with after which tests levels-2x The patient should be advised NOT to share or organ tests
• share personal items or equipment Vaccines and: The Vaccines
• The Hepatitis and transmission can be in children high Individuals will have hepatitis as is minimal, and the should not use the treatment procedure.

Test your knowledge of viral infection diagnosis and symptoms. Questions cover risk factors, stages of illness, immunity, and diagnostic methods. Evaluate your understanding of this viral infection.