Dengue Hemorrhagic Fever 2
Dengue Hemorrhagic Fever
Those cases with gross hemorrhages. A severe illness characterized by abnormal vascular permeability, hypovolemia and abnormal blood clotting mechanism Causative Agent * 4 serotype of the dengue virus (1,2,3 and 4 Group B Arbovirus) * the 4 viruses are antigenically close to each other however, they only give partial cross protection after being infected by any of them
Aedes Aegypti
Bite of the Female Aedes Aegypti (day biting, low flying, breeds in stagnant water, in urban areas). Why female? It is because that they use the blood obtained for laying of eggs. It is the primary vector for the transmission of dengue.
Sources:
1. Infected Persons – virus is present in the blood of patients during the acute phase of the disease and will become a reservoir of the virus 2. Standing water will serve as a breeding place for the mosquitoes
Mode of transmission
By the bit of an infective Aedes Aegypti mosquito
Incubation Period
4-6 days (minimum: 3 days; maximum: 10days)
Pathophysiology
* Each of the 4 types of Dengue virus can cause either classical or dengue hemorrhagic fever. * Virus enters the blood stream * Neutralizing antibodies are produced principally against the virus type * Because of the production of antibodies, and the response of the immune system to the initial attack, constitutional signs and symptoms are manifested * Because of the increasing antigen-antibody complex 1. Increased capillary fragility – brought about by a strong immune complex reaction the produce toxic substance like histamine, serotonin and bradykinin which damages the capillary wall à in an attempt to repair lesions, clotting occurs à DISSEMINATED INTRAVASCULAR COAGULATION 2. Increased capillary permeability – loss of plasma from intravascular space 3. Thrombocytopenia – acute excessive consumption of platelets due to generalized intravascular clotting 4. Decreased blood coagulation factors – initiated by lesions in the
Those cases with gross hemorrhages. A severe illness characterized by abnormal vascular permeability, hypovolemia and abnormal blood clotting mechanism Causative Agent * 4 serotype of the dengue virus (1,2,3 and 4 Group B Arbovirus) * the 4 viruses are antigenically close to each other however, they only give partial cross protection after being infected by any of them
Aedes Aegypti
Bite of the Female Aedes Aegypti (day biting, low flying, breeds in stagnant water, in urban areas). Why female? It is because that they use the blood obtained for laying of eggs. It is the primary vector for the transmission of dengue.
Sources:
1. Infected Persons – virus is present in the blood of patients during the acute phase of the disease and will become a reservoir of the virus 2. Standing water will serve as a breeding place for the mosquitoes
Mode of transmission
By the bit of an infective Aedes Aegypti mosquito
Incubation Period
4-6 days (minimum: 3 days; maximum: 10days)
Pathophysiology
* Each of the 4 types of Dengue virus can cause either classical or dengue hemorrhagic fever. * Virus enters the blood stream * Neutralizing antibodies are produced principally against the virus type * Because of the production of antibodies, and the response of the immune system to the initial attack, constitutional signs and symptoms are manifested * Because of the increasing antigen-antibody complex 1. Increased capillary fragility – brought about by a strong immune complex reaction the produce toxic substance like histamine, serotonin and bradykinin which damages the capillary wall à in an attempt to repair lesions, clotting occurs à DISSEMINATED INTRAVASCULAR COAGULATION 2. Increased capillary permeability – loss of plasma from intravascular space 3. Thrombocytopenia – acute excessive consumption of platelets due to generalized intravascular clotting 4. Decreased blood coagulation factors – initiated by lesions in the