Infection with Borrelia afzelii and manipulation of the egg surface microbiota have no effect on the fitness of immature Ixodes ricinus ticks

Arthropod vectors carry vector-borne pathogens that cause infectious disease in vertebrate hosts, and arthropod-associated microbiota, which consists of non-pathogenic microorganisms. Vector-borne pathogens and the microbiota can both influence the fitness of their arthropod vectors, and hence the epidemiology of vector-borne diseases. The bacterium Borrelia afzelii, which causes Lyme borreliosis in Europe, is transmitted among vertebrate reservoir hosts by Ixodes ricinus ticks, which also harbour a diverse microbiota of non-pathogenic bacteria. The purpose of this controlled study was to test whether B. afzelii and the tick-associated microbiota influence the fitness of I. ricinus. Eggs obtained from field-collected adult female ticks were surface sterilized (with bleach and ethanol), which reduced the abundance of the bacterial microbiota in the hatched I. ricinus larvae by 28-fold compared to larvae that hatched from control eggs washed with water. The dysbiosed and control larvae were subsequently fed on B. afzelii-infected or uninfected control mice, and the engorged larvae were left to moult into nymphs under laboratory conditions. I. ricinus larvae that fed on B. afzelii-infected mice had a significantly faster larva-to-nymph moulting time compared to larvae that fed on uninfected control mice, but the effect was small (2.4% reduction) and unlikely to be biologically significant. We found no evidence that B. afzelii infection or reduction of the larval microbiota influenced the four other life history traits of the immature I. ricinus ticks, which included engorged larval weight, unfed nymphal weight, larva-to-nymph moulting success, and immature tick survival. A retrospective power analysis found that our sampling effort had sufficient power (> 80%) to detect small effects (differences of 5% to 10%) of our treatments. Under the environmental conditions of this study, we conclude that B. afzelii and the egg surface microbiota had no meaningful effects on tick fitness and hence on the R0 of Lyme borreliosis.

Short Communication: Histopathology of red chilli fruit (Capsicum annuum) infected with Colletotrichum acutatum of Java, Indonesia isolates

Muljowati JS, Soesanto L, Nugroho LH. 2021. Short Communication: Histopathology of red chilli fruit (Capsicum annuum) infected with Colletotrichum acutatum of Java, Indonesia isolates. Biodiversitas 22: 874-880. Colletotrichum acutatum isolates from Malang, Temanggung, Kulonprogo, Brebes, Garut, and Pandeglang in Indonesia varied in their ability to produce pigments. In the present study, the histopathological status of red chilli was investigated during the early phase of infection by C. acutatum Java isolate. The results included a description of the histopathological features of red chillies (Capsicum annuum) in the early phase of infection by C. acutatum isolates and the relationship between the origin of the isolates and the time of onset of infection. The red chilli fruits were inoculated with fungal conidia suspension and then the histopathology of chilli fruits was observed at 0 hours (uninfected control), 8 hours, 16 hours, 24 hours, and 32 hours after inoculation. The results showed that C. acutatum isolates from Kulonprogo caused host damage within 8 hours, while the other isolates (from Malang, Brebes, Garut and Pandeglang) began to produce similar symptoms at 16 hours or 24 hours. This study revealed for the first time that pathogenic activity begins at the onset of infection, and the resulting anatomical damage to red chillies begins at different times.

THE EFFICACY OF OXYTETRACYCLINE THERAPY AND THE DURATION OF TREATMENT IN THE COURSE OF BOVINE ANAPLASMOSIS

A total of 27 crossbred calves (12 intacts, 9 splenec­tomised and 6 uninfected control) were sub­cutaneously Inoculated with 2 x 107 Anaplasma marginale infected erythrocytes. Oxytetracycline (at 10mg/kg body weight) was administered in­travenously when the PCV dropped to 16 per cent or below. The pattern of development of parasitaemia, appeared to be similar in both intact and splenec­tomised calves. The spelectomised calves, however, gave higher percentage of parasitaemia. Fluctuation in the PCV followed the same pattern in both groups, but the splenectomised calves were observed to suffer more anaemic crisis than the intact ones. In the intact calves, all those treated once and for 2 consecutive days survived. In the splenectomised calves, all those treated once died, while all those treated for 2 consecutive days survived. It may be concluded that, 2 consecutive ox­ytetracycline treatments (at 10mg/kg body weight) gave better recovery rates in cases of clinical bovine anaplasmosis.

Infection With Borrelia Afzelii Reduces Moulting Time of Lxodes Ricinus Ticks

Arthropod vectors carry vector-borne pathogens that cause infectious disease in vertebrate hosts, and arthropod-associated non-pathogenic microorganisms. Both types of micro-organisms can influence the fitness of their arthropod vectors, and hence the epidemiology of vector-borne diseases. The bacterium Borrelia afzelii, which causes Lyme disease in Europe, is transmitted among vertebrate reservoir hosts by Ixodes ricinus ticks, which also harbour a large diversity of non-pathogenic bacteria. The purpose of this study was to test experimentally whether B. afzelii and tick-associated non-pathogenic bacteria influence the fitness of I. ricinus. Eggs obtained from field-collected adult female ticks were washed with bleach, which reduced the abundance of non-pathogenic bacteria in the hatched I. ricinus larvae by 28-fold compared to larvae that hatched from eggs washed with water. The dysbiosed and control larvae were subsequently fed on B. afzelii-infected or uninfected control mice, and the engorged larvae were allowed to moult into nymphs under laboratory conditions. I. ricinus larvae that fed on B. afzelii-infected mice had a significantly faster larva-to-nymph moulting time compared to larvae that fed on uninfected control mice. In contrast, we found no evidence that B. afzelii infection or larval dysbiosis influenced the four other life history traits of the immature I. ricinus ticks, which included engorged larval weight, unfed nymphal weight, larva-to-nymph moulting success, and immature tick survival. A power analysis found that our sampling effort had sufficient power (>80%) to detect small effects (difference of 5% – 10%) of either B. afzelii infection or larval dysbiosis. Under the laboratory conditions of our study, B. afzelii appears to be a mostly passive passenger in I. Ricinus ticks.

Differential Response of Mycorrhizal Plants to Tomato bushy stunt virus and Tomato mosaic virus Infection

Tomato bushy stunt virus (TBSV) and Tomato mosaic virus (ToMV) are important economic pathogens in tomato fields. Rhizoglomus irregulare is a species of arbuscular mycorrhizal (AM) fungus that provides nutrients to host plants. To understand the effect of R. irregulare on the infection by TBSV/ToMV in tomato plants, in a completely randomized design, five treatments, including uninfected control plants without AM fungi (C), uninfected control plants with AM fungi (M) TBSV/ToMV-infected plants without AM fungi (V), TBSV/ToMV-infected plants before mycorrhiza (VM) inoculation, and inoculated plants with mycorrhiza before TBSV/ToMV infection (MV), were studied. Factors including viral RNA accumulation and expression of Pathogenesis Related proteins (PR) coding genes including PR1, PR2, and PR3 in the young leaves were measured. For TBSV, a lower level of virus accumulation and a higher expression of PR genes in MV plants were observed compared to V and VM plants. In contrast, for ToMV, a higher level of virus accumulation and a lower expression of PR genes in MV plants were observed as compared to V and VM plants. These results indicated that mycorrhizal symbiosis reduces or increases the viral accumulation possibly via the regulation of PR genes in tomato plants.

Comparative Proteomic Analysis of Serum from Pigs Experimentally Infected with Trichinella spiralis, Trichinella britovi, and Trichinella pseudospiralis

Although the available proteomic studies have made it possible to identify and characterize Trichinella stage-specific proteins reacting with infected host-specific antibodies, the vast majority of these studies do not provide any information about changes in the global proteomic serum profile of Trichinella-infested individuals. In view of the above, the present study aimed to examine the protein expression profile of serum obtained at 13 and 60 days postinfection (d.p.i.) from three groups of pigs experimentally infected with Trichinella spiralis, Trichinella britovi, and Trichinella pseudospiralis and from uninfected, control pigs by two-dimensional gel electrophoresis (2-DE) followed by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry. The comparative proteomic analysis of the T. spiralis group vs. the control group revealed 5 differently expressed spots at both 13 and 60 d.p.i. Experimental infection with T. britovi induced significant expression changes in 3 protein spots at 13 d.p.i. and in 6 protein spots at 60 d.p.i. in comparison with the control group. Paired analyses between the group infected with T. pseudospiralis and the uninfected control group revealed 6 differently changed spots at 13 d.p.i. and 2 differently changed spots at 60 d.p.i. Among these 27 spots, 15 were successfully identified. Depending on the Trichinella species triggering the infection and the time point of serum collection, they were IgM heavy-chain constant region, antithrombin III-precursor, immunoglobulin gamma-chain, clusterin, homeobox protein Mohawk, apolipoprotein E precursor, serum amyloid P-component precursor, Ig lambda chains, complement C3 isoform X1, and apolipoprotein A-I. Our results demonstrate that various Trichinella species and different phases of the invasion produce a distinct, characteristic proteomic pattern in the serum of experimentally infected pigs.

245. Plasma and Respiratory Specimen Metagenomic Sequencing for the Diagnosis of Severe Pneumonia in Mechanically-Ventilated Patients

Background Metagenomic sequencing of respiratory microbial communities may overcome the limitations of culture-based pneumonia diagnostics. Nonetheless, respiratory metagenomics requires high-quality specimens, may miss deep-seated infections and cannot distinguish colonization from infection. Plasma microbial cell-free DNA (mcfDNA) sequencing may offer a noninvasive alternative for culture-independent diagnosis and help refine interpretations of respiratory metagenomics. Methods We obtained concurrent plasma and endo-tracheal aspirate (ETA) samples from 29 mechanically-ventilated patients (15 culture-positive, 11 culture-negative pneumonia, 3 uninfected control patients). We performed plasma mcfDNA sequencing (Karius®Test, Redwood City, CA) and ETA metagenomics (MiNION, Oxford Nanopore Technologies). We compared sequencing results with clinical microbiologic cultures for identified DNA pathogens. Results Uninfected control patients had a negative signal for mcfDNA in plasma and oral bacteria in ETA specimens. In culture-positive pneumonia samples, Karius testing identified a median of 2 pathogens per sample (range 0–10), which were concordant with clinical isolates in 11/15 (73%) cases (figure). In 5/11 (45%) of concordant cases, Karius and MiNION suggested polymicrobial infections with additional pathogens not identified by cultures. In culture-negative cases, Karius detected potential pathogens in 8/11 (73% cases), which matched the species identified in ETA specimens by MiNION. In cases of clinical aspiration, Karius detected more organisms (median 8, range 0–14) per sample mainly consisting of oral origin bacteria compared with cases without history of aspiration (median 1, range 0–6, P = 0.04). Conclusion Metagenomic sequencing in plasma and ETA samples showed good concordance between the blood and lung compartments as well as with culture results in pneumonia patients. Metagenomics revealed potential pathogens missed by cultures in ~75% of culture-negative pneumonias and suggested polymicrobial infections especially in cases with aspiration. Further research is needed to evaluate the clinical utility of real-time metagenomics for pneumonia diagnosis in mechanically ventilated patients. Disclosures All authors: No reported disclosures.

In vivo efficacy of lasalocid and pyrimethamine treatments against Anophryoides haemophila, a ciliate pathogen of American lobster Homarus americanus

Lasalocid and pyrimethamine was administered to American lobsters infected with A. haemophila. Lasalocid was found to be toxic and acute mortality was observed, when administered in vivo in both infected and uninfected lobsters. Pyrimethamine was found very efficient to treat these ciliates at repeated doses. The mortality was very low and the mean haemocyte counts remained higher than the uninfected control group. The drug seems to delay the appearance of the ciliates in the haemolymph and to lower the spread of these parasites in the epipodite and the hepatopancreas. In uninfected animals treated with this drug, haemocyte counts were similar to uninfected control group. Furthermore, no pathology was observed, when the drug was administered to uninfected lobsters. Since there is no effective treatment for the control of bumper car disease, on the basis of the results of the present study, we suggest that pyrimethamine is a good drug for the treatment of A. haemoplila infection in lobsters.

Systolic function evaluated with cardiovascular magnetic resonance imaging in HIV-infected patients

Background: Of all areas worldwide, sub-Saharan Africa is worst affected by the HIV and/or AIDS epidemic. Cardiovascular manifestations are very common and are a powerful contributor to mortality, but often go undetected. Cardiovascular magnetic resonance (CMR) is the most reliable method of assessing cardiac function and morphology and, with this in mind, we initiated a cross-sectional study comparing CMR-determined morphological and functional parameters in asymptomatic HIV-infected patients who were not yet on treatment and early in the disease, with HIV-uninfected control patients.Objectives: To ascertain whether there were any morphological abnormalities or systolic functional impairments on CMR in untreated asymptomatic HIV-infected patients, compared with HIV-uninfected control individuals.Methods: The CMR studies were performed using a 1.5-T whole-body clinical magnetic resonance 16-channel scanner (Achieva, Philips Medical Systems, Best, The Netherlands), using a cardiac five-element phased-array receiver coil (SENSE coil). Functional assessment was performed on 36 HIV-infected patients and the findings compared with 35 HIV-uninfected control patients who were matched for age and sex.Results: There was no significant difference in systolic function between the HIV-uninfected and the HIV-infected patients. The left ventricular end diastolic mass (LVEDM) was slightly higher in the HIV-infected group, but this was statistically insignificant.Conclusion: No significant differences were found regarding the CMR systolic functional analysis and morphological parameters between the HIV-infected and the healthy volunteers.