has been hampered by the difficulty of evaluating host resistance in the field and lack of reliable screening techniques.
Lack of reciprocity refers to the difficulty of sending host physicians abroad as well as failed attempts at building long-lasting relationships with foreign institutions.
Environmental heterogeneity significantly increases the difficulty of predicting host and pathogen fitness-related trait variation as the environment may alter both selection specificity and strength (Lazzaro and Little 2009; Wolinska and King 2009), leading to variation in specific gene frequencies in nature.
The poorly characterized capacity of bats to compensate for and respond to infection during hibernation demonstrates the difficulty of understanding how host-pathogen interactions influence disease manifestation and mortality.
These results illustrate the logical difficulties of interpreting host-parasite interactions without considering an explicit time dimension.
In light of the difficulty of total expulsion of host tissue during nucleic acid extraction, this method offers (at least with respect to protein-coding genes) an a posteriori bioinformatic solution to ensure proper identification and filtration of contaminant sequences.
However, spatial heterogeneity within individual host trees is often overlooked in survey methods, possibly due to the logistical difficulty of accessing various components of host plants.
Untangling S. japonicum physiology can have important ramifications for efforts to control schistosmiasis, which remains a substantial challenge in endemic areas due to the difficulty of eradicating the snail intermediate hosts.
It is easy to think of Ebola as an outlier, a rare and exotic disease that is particularly hard to learn about due to the sporadic nature of its outbreaks, the remoteness of the communities it affects, and the difficulty of containing transmission from its animal hosts.
On the policy level, it is acknowledged that the capacity of embassies in terms of human and financial resources, compounded by the relative difficulty of negotiations in cases where the host government has no effective control and legitimacy will make it difficult to ensure that the ideal conditions in repatriating OFWs will be done.
