Hanta virus is a common virus that causes two syndromes: hantavirus pulmonary syndrome and hemorrhagic fever with renal syndrome. Rodents are the natural host for this virus, and humans become infected after coming into direct contact with the rodents' urine, droppings and saliva. Patients exposed to the virus do not develop symptoms until weeks after the initial exposure.
Initial Symptoms
The initial symptoms of hantavirus infection are nonspecific, and consist of fever, chills, headaches, muscle aches (particularly of the shoulder, back and thighs), nausea, vomiting and diarrhea (which leads to dehydration), dizziness and occasional cough.
Pulmonary symptoms
Hantavirus pulmonary syndrome results in noncardiogenic pulmonary edema. Usually the heart's right ventricle pumps blood to the lungs, where it becomes oxygenated and returns to the left side of the heart to be pumped to the rest of the body. In cardiogenic pulmonary edema, the heart cannot pump the blood efficiently, so fluid accumulates in the lungs, resulting in pulmonary edema. In hantavirus pulmonary syndrome, the fluid that accumulates in the lungs is not the result of inefficient heart pumping, but rather increased leakage of fluids in the lungs' alveoli, the microscopic pouches at the end of the lung's airway tree where oxygen exchange takes place with the blood stream. Patients with pulmonary edema develop shortness of breath, rapid breathing, cough, and pain on taking a deep breath. The pulmonary edema also leads to decreased oxygen in the blood stream and the tissues. Lungs sounds become wet, with a characteristic crackling sound. Patients with pulmonary edema may need diuretics to eliminate the excess fluid and occasionally may need mechanical ventilation to help them breathe.
Hemorrhagic Fever With Renal Syndrome
This syndrome develops several weeks after exposure. After the initial nonspecific symptoms, patients develop acute shock, with low blood pressure, decreased perfusion to the extremities and kidney failure. The kidney failure reduces the organ's ability to filter the blood, resulting in an accumulation of toxic substances and electrolyte abnormalities, like high potassium, which can lead to an erratic heart rate, or arrhythmias. Patients with this syndrome can appear flushed, especially in the face and neck. They might also exhibit low counts of platelets, the main cells involved in the clotting of blood. This can lead to petechia, or small spots of spontaneous bleeding, especially in the axilla and palate. It can also lead to conjunctival hemorrhage, or bleeding of capillaries in the conjunctiva, the white area of the eyes.
