Intraspecific Gene Flow and Vector Competence among Periplaneta americana Cockroaches (Blattodea: Blattidae) in Central Texas

One of the most overlooked areas in forensic entomology is urban, which applies\nto insects and their arthropod relatives that have interactions with humans, their\nassociated structures, and companion animals. American cockroaches, Periplaneta\namericana (L.), are common pests of urban environments. Analyzing spatial distribution\nof P. americana populations in an artificial, outdoor environment provided insight of\ngene flow among populations collected in central Texas. This information provides for a\nbetter understanding of how and if populations were segregated, or if there was a single\nunified population. Populations can be genetically differentiated through determining\nvariation of specific gene regions within populations. This study revealed a ubiquitous\ndistribution of cockroach populations, and their ability to indiscriminately inhabit areas\nwithin an urban environment. Overall, cockroaches were identified from a large\ninterbreeding population with no discernable relationship between genetic variation of P.\namericana and spatial distribution.\nIdentifying cockroach populations is relative to understanding the ability of\nsurrogate species indirectly affecting man by their ability to transfer disease-causing organisms including bacteria. This may have potentially deleterious health consequences\non animal and/or human populations. There are several pathogens associated with\ncockroaches which are overlooked during diagnosis of sudden ailments with symptoms\nbeing similar to food-borne illnesses, including abdominal cramping, diarrhea, nausea,\nand fever. Analyzing spatial distributions of Escherichia coli and Campylobacter spp. in\nrelationship to collected cockroaches allowed for prevalence of bacteria species to be\nidentified among populations. The prevalence of bacteria isolated from total populations\ncollected indicated a high prevalence (92.3%) of bacteria carried by the exoskeleton of\nP. americana. Gram-negative bacteria acquisition and dissemination of organisms such\nas E. coli was prevalent on campus. Screening for E. coli 1057:H7 and Campylobacter\nspp. resulted in no positive colony growth. The lack of Campylobacter spp. growth from\ncuticular surfaces may have resulted from undesirable conditions required to sustain\ncolony growth. Data from this study corroborates the potential ability of cockroaches to\nmechanically transmit pathogens.