Because Hepatitis viruses are usually transmitted via infected blood, cockroaches never were suspected of being able to infect humans. But, unlike a mosquito, cockroaches are transmitting viruses via the so-called ‘mechanical route’. This simply means that if you squash an infected insect, its contaminated blood may have the capacity to infect via direct or indirect contact. Remember, it only takes a minuscule wound for the virus to enter your system.
Which is exactly what has happened before. An outbreak of Hepatitis A in a Los Angeles housing project in the late 1950s was eventually traced back to an infestation of coackroaches. From 1956 to 1959, the Carmelitos Housing Project represented 39% of all cases of Hepatitis A in Los Angeles County with numbers of the infected steadily increasing through the years. It was only until a full-scale cockroach control program was the outbreak halted. Two years following the program, incidences of Hepatitis A dropped to 0.0% and cockroaches traversing between the sewage system and the houses were pinpointed as the source of the epidemic.
Hepatitis A Virus is commonly spread via eating or drinking food or water contaminated with infected feaces. Because those conditions also favour cockroaches, hardly anybody will suspect the cockroach as the vector. It is quite possible that incidences of Hepatitis A in which cockroaches are the causal species are seriously underreported throughout the world.