Abstract
PurposeThe aim of this study was to investigate protozoan cysts and oocyts in the faecal pellets of the German cockroach (Blattella germanica), with emphasis on the prevalence of Lophomonas blattarum.MethodsThirty adult Blattella germanica (12 males; 18 females) were trapped near Madrid, Spain. Expelled faecal pellets were collected in the laboratory over 5 days in two plastic containers. Protozoan cysts from one container were weighted and those in the other used for morphologically identification.ResultsProtozoan cysts/oocysts per gram of faecal pellet were: Nyctotherus sp. (0.0019/g), Entamoeba (0.0007/g), Balantidium coli (0.0001/g), Lophomonas blattarum (0.00038/g). Observation of 189 protozoan cysts/oocysts indicated the following prevalence: Nyctotherus sp. 65 (34.4%); Gregarina spp. 34 (18%); Entamoeba sp. 24 (12.7%); Cryptosporidium sp. 17 (9%); Coccidia 16 (8.4%); Lophomonas blattarum 13 (6.8%); Balantidium coli 4 (2.1%); and unclassified 16 (8.4%).ConclusionLophomonas blattarum has previously been demonstrated in the gut of cockroaches, but this is the first assessment of the prevalence in Blattella germanica in faecal pellets. The presence of protozoa in faecal pellets provides some evidence for one step in a hypothesised route of respiratory infection whereby protozoa from household insects enter the respiratory tract.
Highlights
This paper examines one step on a hypothesised pathway, whereby protozoa from cockroach intestine are excreted in encysted form in faecal pellets, present in household dust, and inhaled into the human respiratory tract
We have described the presence of a multi-flagellated protozoon, L. blattarum, in the gut of B. germanica [5]
Nyctotherus sp. (0.00019/g), were the most frequently observed cysts and five types which belong to pathogenic microorganisms were found (Entamoeba, Cryptosporidium, Coccidia, L. blattarum and Balantidium coli), representing 0.00021 cysts per gram of faecal pellets
Summary
This paper examines one step on a hypothesised pathway, whereby protozoa from cockroach intestine are excreted in encysted form in faecal pellets, present in household dust, and inhaled into the human respiratory tract. Cockroaches are a group of arthropods that are closely associated with an anthropogenic environment, which can adversely impact on human health. The adverse effect that has been best evidenced is allergy to cockroach proteins (mainly proteases) present in its body, in saliva, intestinal contents, or in its faecal pellets, which are associated with asthma in some patients [1]. The German cockroach (Blattella germanica), can carry medically important parasites on its surface and inside its digestive tract, including protozoa such as Ballantidium coli, Blastocystis hominis, Entamoeba histolytica, Giardia duodenalis, and Toxoplasma gondii [3, 4]. We have described the presence of a multi-flagellated protozoon, L. blattarum, in the gut of B. germanica [5]
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