While the number of deaths due to nearly every disease have decreased, deaths due to HIV/AIDS have increased fourfold. Childhood diseases include pertussis, poliomyelitis, diphtheria, measles and tetanus. Children also make up a large percentage of lower respiratory and diarrheal deaths. In 2012, approximately 3.1 million people have died due to lower respiratory infections, making it the number 4 leading cause of death in the world. Historic pandemics
With their potential for unpredictable and explosive impacts, infectious diseases have been major actors in human history. A pandemic (or global epidemic) is a disease that affects people over an extensive geographical area. For example:

Plague of Justinian, from 541 to 542, killed between 50% and 60% of Europes population. The Black Death of 1347 to 1352 killed 25 million in Europe over 5 years. The plague reduced the old world population from an estimated 450 million to between 350 and 375 million in the 14th century. The introduction of smallpox, measles, and typhus to the areas of Central and South America by European explorers during the 15th and 16th centuries caused pandemics among the native inhabitants. Between 1518 and 1568 disease pandemics are said to have caused the population of Mexico to fall from 20 million to 3 million. The first European influenza epidemic occurred between 1556 and 1560, with an estimated mortality rate of 20%. Smallpox killed an estimated 60 million Europeans during the 18th century (approximately 400,000 per year).
Individuals can get genetic testing done to see if they are a carrier of the trait, and if so may choose to complete genetic counseling to better understand the disorder and help manage family planning. Parents can choose to do prenatal genetic testing for the disorder to determine if their child will have the disease. The only risk factor is if both parents of a child carry the recessive allele linked to the disorder. Mechanism
Individuals with the disorder have a mutation to their fibrinogen gene that prevents the formation of the protein. In normal conditions, fibrinogen is converted to fibrin when it is cleaved by the enzyme thrombin in the blood. The newly formed fibrin forms a fiber-rich network that helps trap red blood cells to start the coagulation process and form a clot. Since there is no fibrinogen present during afibrinogenemia, fibrin can not be formed to aid in this process. Diagnosis
Diagnostic tests
When a problem of fibrinogen is suspected, the following tests can be ordered:

PT
PTT
Fibrinogen level in blood (total and clottable)
Reptilase time
Thrombin timeBlood fibrinogen levels of less than 0.1 g/L and prolonged bleeding test times are indicators of an individual having afibrinogenemia.A suspicion of congenital afibrinogenemia may appear on a platelet aggregation function test. Treatment
The most common treatment is fibrinogen replacement therapy, including cryoprecipitate, blood plasma, and fibrinogen concentration transfusions to help with bleeding episodes or prior to surgery. Although some thrombotic complications have been reported following replacement theory, transfusions of fibrinogen concentrate are widely considered to be the most beneficial.