According to a new study, researchers for the first time used Positron Emission Tomography (PET) imaging to study brain inflammation following Zika virus infection in mice. The imaging studies allow longitudinal studies of the same animal, and the progression of the disease over time. The study published online in the journal Molecular Imaging and Biology.

According to Thomas M. Bocan from the U.S. Army Medical Research Institute of Infectious Diseases (USAMRIID), small-animal imaging has become an important research tool for preclinical studies of infectious diseases. PET is a highly sensitive molecular imaging technique that can be used to visualize a variety of biological processes in live animal models.

The traditional methods of infectious disease research using animal models provided limited information about disease progression. The investigators had to analyze tissues from those animals to get information. While, imaging studies allow us to gather enhanced information through longitudinal studies of the same animal during the course of the infection.

According to the WHO, Zika virus was initially identified in monkeys (year 1947), then in humans (year 1952). The virus was widespread among the Americans, and the virus transmitted through various means like mosquito bite and sexual transmission. The zika virus infection during pregnancy was linked to congenital brain abnormalities (microcephaly). The Zika virus is a trigger of Guillain-Barré syndrome.

In ongoing research to investigate the link between Zika virus and neurological disorders, the pathogenic mechanisms causing the disease should be known. The USAMRIID team evaluates the ability and sensitivity of PET imaging, using a probe called [18F] DPA-714 to detect and quantify neuroinflammation in Zika virus-infected mice.

The results suggest that the levels of Zika virus in the mouse brain increased from day 3 to day 10 post-infection. Over this time-interval, the mice showed a 2- to 6-fold increase in global brain neuroinflammation using [18F] DPA-714 PET imaging.

The significant role played by global neuroinflammation in the progression of Zika virus infection was highlighted.  While, the ability of [18F] DPA-714 PET imaging to detect and quantify Zika virus-related neuroinflammation was also demonstrated. The study was conducted using the mice model, and the infection had spread throughout the brains of the mice.

The use of PET and other noninvasive imaging technologies reduces the number animals in a study by permitting the use of animals as their own controls. Besides, therapeutic agents can be developed and tested using imaging technologies that are directly translatable to the clinic.

"The future is bright for the application of imaging in infectious diseases," said Bocan. "Measures of virus and bacteria distribution and the consequences of infection can be assessed in real time in the same subject. In addition, treatment with countermeasures can be evaluated with a better understanding of the state of disease progression."