COMMUNITY HEALTH NURSING

Epidemiology of Dengue Syndrome (lectures) - by Mrs Tara Shah

 
- Dengue is known as an endemic disease of tropical & subtropical regions.

- It was considered a disease very frequent on kids, but recently an increase was reported on adult people.

- It is caused by 4 flavivirus serotypes (DEN-1, DEN-2, DEN-3 & DEN-4).

- The incidence of dengue fever (DF) & dengue hemorrhagic fever (DHF) has increased thirty-fold globally in the last 4 decades & >half the world’s population is now threatened with infection from dengue virus.

 
Manifestations of Dengue Syndrome

 

CLINICAL FEATURES

DF is an acute viral disease manifesting with-
- Myalgias
- Headache
- Retro-orbital pain
- Vomiting
- Maculo-papular rash
- Leucopenia & thrombocytopenia

DHF is characterized by-

- High fever, hemorrhagic phenomena

- Hepatomegaly & signs of impending circulatory failure (postural hypotension resting tachycardia, diaphoresis).

- Significant thrombocytopenia with concurrent hemoconcentration

 

TRANSMISSION OF DENGUE VIRUS
Over the last few decades, the earlier principal vector of dengue virus in Asia,
- Aedes albopictus - has been replaced by
- Aedes aegypti.

Management

- Hydration (oral and/or IV)

- Control of high fever by sponging & Paracetamol

- Platelet Transfusion

 

PREVENTION

Community participation in vector control–

- eliminating larval habitats
- indoor space-spray insecticides & mosquito nets while sleeping.

Use insect repellents

 

Epidemiology of Lymphatic Filaria (LF) (lectures) - by Mrs Tara Shah

LF

- The term “lymphatic filariasis” covers infection with three closely related nematode worms- W. bancrofti, Brugia malayi & Brugia timori.

- All 3 infections are transmitted to man by the bites of infective mosquitoes (Culex quinquefasciatus) .

- Though LF is not fatal, the disease is responsible for considerable suffering, deformity & disability.

- WHO considered as a major public health problem with an increasing prevalence worldwide.

- 20% of the world's population in some 80 endemic countries located in tropical areas of the world are at risk of infection.

- Over ⅓ of the population at risk lives on the Indian sub-continent.

 

Clinical manifestations

Approx. ⅓ of infected individuals present with overt clinical manifestations:
- Lymphoedema & elephantiasis of the limbs or genitals,
- Hydrocoele, chyluria
- Pneumonitis, or recurrent infections associated with damaged lymphatics.
- Serious psychosocial consequences often have with profoundly disabling lesions.

 

Prevalence in Nepal

- The overall prevalence of lymphatic filariasis from a 4,488-sample population was 13% and 33/37 districts were found to be endemic.

- On the basis of geographical data, the highest number of cases was found at altitudes between 500–700 m.

 

Burden of disease in Nepal

Age:
- The highest positive rate of 15.8% in 46–50 age group & the lowest (10%) in the 36–40 age group.

Sex:
- 57.4% among males (The sample of 4,488)

Geographical distribution:
- Up to 40% in terai (Bardiya) against o% in hill & mountain.

Mode of transmission
The man-mosquito transmission
(Infective biting rate)

 

Incubation period:
The most common period - 8 to 16 months

Filaria Survey

- Mass blood survey at night (Demonstration of living parasite)
- Clinical survey
- Serological tests- to detect antibodies

- Xenodiagnosis- Mosquito allow to feed on the pt. & then dissected 2 weeks later.

- Entomological survey:
General mosquito collection from houses & dissection of female mosquito is done.

 

Control measures

Chemotherapy

Diethylcarbamazine (DEC) 6 mg/kg body wt/ day for 12 days

Filaria control in community:
- Mass therapy
- Selective treatment
- DEC medicated salt
- Ivermectin

Vector control

 

 

Arthropod Borne Infections (lectures) - by Mrs Tara Shah

Arthropod Borne Infections - Malaria, Filariasis, Dengue Syndrome

Epidemiology of Malaria


- 300-500 million clinical cases of malaria occur each year.

- 2.5 million die from malaria each year

- Malaria is usually a 'rainy season disease‘

- Deforestation, population migration & changes in agricultural practice have profound effect on malaria transmission.

- Urban malaria is becoming an increasing problem in many countries.

- In many areas the transmission of malaria varies considerably over short distances, and severe disease is common when non-immune individuals enter these areas.

- Epidemics are caused by migration (i.e. Introduction of susceptible hosts).

- Epidemics have occurred in North India, Sri Lanka, South East Asia, & Africa.

 

Malaria

Malaria is a common tropical disease caused by a protozoa plasmodium through the bite of female anopheles mosquito.
Types:
Mainly 4 types of plasmodium infection causing malaria-
- Plasmodium falciparum (Malignant tertarian malaria)
- Plasmodium Vivax* (Begign tertarian malaria)
- Plasmodium malaria
- Plasmodium oval

Factors Affecting Transmission

- Distribution & Abundance of the mosquito vector
- Temperature & extent of water for larval breeding
- Seasonal Fluctuation of Mosquito Populations
- Vectoral Capacity of the common vector species
- Duration of Conditions Suitable for Mosquito Survival

 

Life Cycle of Malaria

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Clinical features

Onset
- Abdominal pain
- Nausea
- Dry cough
- Malaise

Fever: 3 stages
- Cold stage: Sudden onset of fever with rigor and sensation of extreme cold lasting for 15 minutes to an hour
- Hot stage: Temp. rise up to 410C (1060F) headache lasting for 2 to 6 hours
- Sweating stage: Profuse sweating last for 2 to 4 hours

Organo-megaly
- Liver moderately enlarged and tender
- Spleen palpable in acute cases

Miscellaneous
- Herpes simplex
- Jaundice (rarely)

Investigations

Hemogram:
- Normochromic normocytic anemia
- Malarial parasite (M.P.) visible on the peripheral smear examination
- Bone marrow
- Splenic puncture

 

Complications

- Coma (Cerebral malaria)
- Hemolytic anemia
- Renal failure
- Pulmonary edema

 

Treatment

- Chloroquine: 600mg (base) followed by 150mg* BD* 4 days
- Primaquine: 15mg BD* 15 days
- Pyrimethamine 25 mg and Sulfadoxine 500mg stat and after 1 week (2 doses)
- Quinine hydrochloride: I.V. for cerebral malaria

 

Prophylaxis

- To prevent mosquito breeding spaces

- Protective measures

- Travelers to endemic areas must take Chloroquine 300mg/week or Pyrimethamine 25mg/week for 2 weeks prior & at least 4 weeks after leaving endemic area