The onset is similar to typical dengue fever. The condition suddenly worsens after 2-5 days of fever, with massive bleeding and shock in multiple organs, hemoconcentration, thrombocytopenia, leukocytosis, and hepatomegaly.

single-stranded positive strand RNA

Contains type and group specific antigens

It can survive for 5 years when stored in human serum at -20℃ and for 8 years at -70℃.

It can be inactivated at 60℃ for 30min or 100℃ for 2min.

Can be inactivated with acid, detergent, ether, ultraviolet light or 0.65% formaldehyde

New epidemic area: all are susceptible, mainly adults

Endemic areas: mainly children

Consolidated immunity against the same type of viruses and can last for many years

Partial immunity to heterotypic viruses, but only for a few months

Recovering from the initial infection and being infected again with other serotypes carries the risk of severe disease

Other group B arboviruses: some degree of cross-immunity (Japanese encephalitis virus)

Tropical and subtropical regions: Southeast Asia, Pacific Islands, Caribbean

China: Hainan, Taiwan, Guangdong, Guangxi, Hong Kong, Macau

popular way

The summer and autumn rainy seasons are from May to November in Guangdong and from March to December in Hainan.

In endemic areas, the incidence rate tends to increase every other year, but in recent years the epidemic cycle has often been irregular.

Dengue virus (mosquito) → human → capillary endothelial cells and monocyte-macrophage system → blood (first viremia)

Relocalizes in the monocyte-macrophage system and replicates in lymphoid tissue → blood (second viremia)

Antiviral antibodies Dengue virus → immune complex

Degeneration of the liver, kidneys, heart and brain

Skin rash biopsy showed swelling of small blood vessel endothelial cells, perivascular edema, and mononuclear cell infiltration, with extensive extravascular hemorrhage in the ecchymosis.

Focal hemorrhage, cerebral edema and encephalomalacia in the subarachnoid space and brain parenchyma are seen in patients with cerebral type.

In severe cases, focal necrosis and cholestasis of liver lobules, lobular pneumonia, and pulmonary lobular abscesses are seen.

promoting antibodies

Superinfection: two different types of infection

Antibody enhancement

Virus strain: Type II

Age: More common in children

Systemic capillary endothelial damage, leading to bleeding and plasma protein leakage

Perimicrovascular hemorrhage, edema, lymphocyte infiltration, and proliferation of the monocyte-macrophage system

Divided into three phases: acute fever phase, extreme phase, and recovery phase

A severe type of dengue fever. The onset is similar to typical dengue fever. The condition suddenly worsens after 2 to 5 days of fever, with massive bleeding and shock in multiple organs, and a high mortality rate.

Course of disease

Performance

Course of disease

Performance

Course of disease

Performance

2-5 days, with typical clinical manifestations of dengue fever

Shock, massive bleeding from multiple organs

Hepatomegaly, positive bundle-arm test

Central respiratory failure is the main cause of death

Severe dengue without shock (bleeding only)

Dengue shock syndrome (hemorrhagic shock)

White blood cells and thrombocytopenia

A small amount of protein, red blood cells, etc. can be seen, and casts may appear.

Transaminases and lactate dehydrogenase are elevated, and cardiac enzymes, urea nitrogen, and creatinine are elevated in some patients.

Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were mildly and moderately elevated

A few patients have increased total bilirubin and decreased serum albumin

Coagulation function: decreased fibrin, prolonged prothrombin time and partial thromboplastin time

specimen collection

Antigen test

Antibody testing

Double serum: 4 times higher, confirmed

RT-PCR, virus isolation (dry suckling mouse brain or C6/36 cell line)

Platelets＜100×10⁹/L

Hematocrit increased by more than 20%

Severe dengue fever without shock Shock → Dengue shock syndrome

Influenza, measles, scarlet fever, epidemic hemorrhagic fever, leptospirosis, scrub typhus

drug rash

Bed rest, liquid or semi-liquid diet, and mosquito-proof isolation until the fever is completely reduced

Monitor consciousness, vital signs, urine output, platelets, HCT changes, etc.

most important

High fever: physical cooling, use with caution to reduce fever

Dehydration: replenish fluids promptly, but do not abuse intravenous drips

Severe toxemia: low-dose adrenocortical hormone

Bleeding: Hemostatic drugs, fresh blood transfusion

Brain Type: Dehydration, Hormones

Sedative and analgesic: diazepam, cranialin

Same as above for electrolyte dynamic monitoring

The principle is to maintain good tissue and organ perfusion

Give balanced salts and other crystalloid solutions, and patients with severe exudation should promptly supplement albumin and other colloid solutions.

Active fluid replacement, corticosteroids, and vasoactive drugs

Hemostasis - local hemostasis if the bleeding site is clear, and antacids for gastrointestinal bleeding

For severe bleeding, red blood cells should be transfused promptly according to the condition

Severe bleeding accompanied by significant platelet reduction requires platelet transfusion

Pay attention to the monitoring and treatment of complications of other organs