Progress in loop-mediated isothermal amplification assay for detection of Schistosoma mansoni DNA: towards a ready-to-use test.

Schistosomiasis is one of the most prevalent Neglected Tropical Disease, affecting approximately 250 million people worldwide. Schistosoma mansoni is the most important species causing human intestinal schistosomiasis. Despite significant efforts in recent decades, the global disease burden of schistosomiasis remains extremely high. This could partly be attributed to the absence of accurate diagnostic tools, primarily in endemic areas. Loop-mediated isothermal amplification (LAMP) is increasingly used in molecular diagnostics as a field-friendly alternative to many other complex molecular methods and it has been proposed as an ideal candidate for revolutionizing point-of-care molecular diagnostics. In a previous work, a LAMP-based method to detect S. mansoni DNA (SmMIT-LAMP) was developed by our research group for early diagnosis of active schistosomiasis in an experimental infection murine model. The SmMIT-LAMP has been further successfully evaluated in both human stool and snail samples and, recently, in human urine samples. In this study, we developed an important improvement for SmMIT-LAMP molecular assay, transforming it into a cold maintenance dry format suitable for potentially manufacturing as kit for ready-to-use for schistosomiasis diagnosis. This procedure could be applied to create dry LAMP kits for a laboratory setting and for diagnostic applications for other neglected tropical diseases.

Increased prevalence of Rickettsia aeschlimannii in Castilla y León, Spain.

We report the increased prevalence recorded in recent years of Rickettsia aeschlimannii in Hyalomma marginatum marginatum ticks removed from human subjects in Castilla y León (NW, Spain). Additionally, a simultaneous infection with R. aeschlimannii and Anaplasma phagocytophilum in two H. marginatum marginatum ticks is reported for the first time.

The seroprevalence of human infection with Rickettsia slovaca, in an area of northern Spain.

An epidemiological survey was undertaken to explore human exposure to Rickettsia slovaca in two provinces of northern Spain. When IFAT were used to test 200 members of the general population for antibodies to rickettsiae of the spotted-fever group, six (3.3%) were found positive, presumably, since Dermacentor is one of the most common genera of human-biting tick in the study area, for antibodies to R. slovaca. Thirty-one (16.9%) of an additional 183 subjects who presented shortly after being bitten by ticks were also found seropositive. The difference in seroprevalence between the general and the tick-bitten populations was significant. Subject gender had no influence on seroprevalence in either population, although, in the tick-bitten group, age and occupation did have a significant influence on the prevalence recorded. Immunoblotting was used to confirm the presence of antibodies in the five subjects, all from the tick-bitten group, found to have acute infections. Three D. marginatus ticks obtained from three of these acute cases were found PCR-positive for R. slovaca DNA.

Detection of antibodies to tick salivary antigens among patients from a region of Spain.

With a view to determine which tick species bite humans most frequently in the province of Soria (Spain) and to know whether these species act as vectors of Rickettsia conorii and/or Borrelia burgdorferi, we analysed the presence of antibodies against salivary proteins of several tick species and of antibodies against R. conorii and B. burgdorferi sensu lato in 102 samples of serum. The sera were collected from 63 patients who were treated for tick bites at the health services of the Soria Health Area. Thirty-nine percent of the patients displayed antibodies against Dermacentor marginatus; 21% against Ixodes ricinus, and 6% against Rhipicephalus sanguineus. IgM antibodies against R. conorii were found in 15 patients, but none of the patients included in the study displayed IgG/IgM Abs against B. burgdorferi sensu lato. In 30% of the patients bitten by I. ricinus and in 24% bitten by D. marginatus, antibodies against R. conorii were found. None of the patients who had been bitten by R. sanguineus expressed antibodies against this pathogen. The results obtained here suggest that D. marginatus and I. ricinus are the main vectors of the spotted fever group rickettsiae in our environment and that the role of R. sanguineus in the transmission of these rickettsiae is debatable.

Tick-bite-induced anaphylaxis in Spain.

Although there are very few reports of human anaphylaxis induced by tick bites, two such cases have recently been seen in Salamanca, Spain. To identify the tick species responsible, salivary-gland extracts from six species of hard tick and two of soft tick were prepared and used as allergens/antigens in skin-prick tests and serological analyses. For each case, the results of the skin tests were positive for several species of hard tick but negative for the soft ticks. ELISA and western blots revealed high titres of IgG against hard ticks (but not soft ticks) in the sera from both cases. However, serum from only one of the cases was found to be ELISA- and western-blot-positive for tick-specific IgE. Accordingly, the anaphylaxis seen in one case was IgE-mediated whereas that in the other case appeared to be IgE-independent. In both cases, most of the tick-specific antibodies only recognized carbohydrate epitopes. High levels of cross-reactivity between the salivary-gland extracts from several species of hard tick made it impossible to identify which species was responsible for each anaphylactic reaction, although the immunological results seem to point to Ixodes ricinus.

Molecular detection of Ehrlichia phagocytophila genogroup organisms in larvae of Neotrombicula autumnalis (Acari: Trombiculidae) captured in Spain.

Twenty unfed larvae of Neotrombicula autumnalis (Acari: Trombiculidae) collected on vegetation in the north of Spain were examined by polymerase chain reaction for Borrelia burgdorferi (s.l.). rickettsiae, and the Ehrlichia phagocytophila genogroup. At least 10% of the larvae were found to contain granulocytic ehrlichiae. Because the larvae were unfed, they would necessarily have inherited the bacteria through a transovarian transmission pathway.