Without regarding any other research on this topic, this particular paper has some interesting notes that may be considered. The sample size (52) is somewhat small, and the humans in this sample are already obese. (Even) the N-AGPT group (no antibodies found) had a 30.7 BMI on average. This makes it difficult to conclude that the virus was the cause of obesity based on this paper alone, as the entire sample set was obese by definition (BMI >30). At the very best one could infer that the level of obesity was affected by the virus to some extent.