Reservoir Of Infection Research Articles

HIV DNA Levels in Persons Who Acquired HIV in the Setting of Long-Acting Cabotegravir for HIV Prevention: Analysis of Cases from HPTN 083 and 084.

We evaluated HIV DNA levels in individuals who received long-acting cabotegravir (CAB-LA) or tenofovir disoproxil fumarate/emtricitabine (TDF/FTC) pre-exposure prophylaxis in the HPTN 083 and 084 trials and had HIV DNA testing performed to help determine HIV status. HIV DNA testing was performed using peripheral blood mononuclear cell (PBMC) samples collected after a reactive HIV test was obtained at a study site. DNA was quantified using droplet digital PCR (lower limit of detection [LLOD]: 4.09 copies/million PBMCs). Final HIV status and the timing of the first HIV-positive visit were determined by an independent adjudication committee based on HIV test results from real-time site testing and retrospective testing at a centralized laboratory. HIV DNA testing was performed for 133 participants [21 HIV-positive (7 CAB-LA arm, 14 TDF/FTC arm) and 112 HIV-negative; 1-6 tests/person]. For persons with HIV, the time between the first HIV-positive visit and collection of the first sample for DNA testing was a median of 81 days for those receiving CAB-LA (range 41-246) and 11 days for those receiving TDF/FTC (range 3-127). Four (57.1%) of the seven CAB-LA cases with infection had a low initial DNA result [three detected <LLOD; one near the LLOD (4.2 copies/106 PBMCs); in 2/4 cases, the DNA level was still <10 copies/106 PBMCs ≥40 weeks after the first HIV-positive visit. In contrast, only 3/14 (21.4%) of the TDF/FTC cases had a low or negative initial DNA test result (one not detected; two <10 copies/106 PBMCs). In this study, the time between the first HIV-positive visit and the first DNA test was longer in the CAB-LA cases than the TDF/FTC cases. Despite this difference, low or undetectable DNA levels were more frequently observed in the CAB-LA cases. This suggests that CAB-LA exposure may limit seeding of the HIV reservoir in early infection.

Noninvasive in vivo photoacoustic detection of malaria with Cytophone in Cameroon

Current malaria diagnostics are invasive, lack sensitivity, and rapid tests are plagued by deletions in target antigens. Here we introduce the Cytophone, an innovative photoacoustic flow cytometer platform with high-pulse-rate lasers and a focused ultrasound transducer array to noninvasively detect and identify malaria-infected red blood cells (iRBCs) using specific wave shapes, widths, and time delays generated from the absorbance of laser energy by hemozoin, a universal biomarker of malaria infection. In a population of Cameroonian adults with uncomplicated malaria, we assess our device for safety in a cross-sectional cohort (n = 10) and conduct a performance assessment in a longitudinal cohort (n = 20) followed for 30 ± 7 days after clearance of parasitemia. Longitudinal cytophone measurements are compared to point-of-care and molecular assays (n = 94). Cytophone is safe with 90% sensitivity, 69% specificity, and a receiver-operator-curve-area-under-the-curve (ROC-AUC) of 0.84, as compared to microscopy. ROC-AUCs of Cytophone, microscopy, and RDT compared to quantitative PCR are not statistically different from one another. The ability to noninvasively detect iRBCs in the bloodstream is a major advancement which offers the potential to rapidly identify both the large asymptomatic reservoir of infection, as well as diagnose symptomatic cases without the need for a blood sample.

Camelpox Virus in Western Kazakhstan: Assessment of the Role of Local Fauna as Reservoirs of Infection.

This article investigates the role of local fauna in Western Kazakhstan as potential reservoirs of the camelpox virus (CMLV). The study emphasizes analyzing possible sources and transmission pathways of the virus using polymerase chain reaction (PCR) and serological methods, including virus neutralization tests and enzyme-linked immunosorbent assays (ELISA). Samples were collected from both young and adult camels, as well as rodents, ticks and blood-sucking insects in the Mangystau and Atyrau regions. The PCR results revealed the absence of viral DNA in rodents, ticks and blood-sucking insects; also, the ELISA test did not detect specific antibodies in rodents. These findings suggest that these groups of fauna likely do not play a significant role in the maintenance and spread of CMLV. Consequently, the primary sources of transmission are likely other factors, potentially including the camels themselves. The study's results indicate the need to reassess current hypotheses regarding infection reservoirs and to explore alternative sources to enhance strategies for the control and prevention of the camelpox virus.

Clinical inertia in onychomycosis treatment: results from the Illuminating Dialogues and Insights in Onychomycosis Management (IDIOM) survey.

Onychomycosis is a fungal infection of the nail that can serve as a reservoir for tinea infections in other parts of the body and can be transmitted to other individuals. As the disease progresses, it can lead to functional impairment, such as difficulties in walking, and negatively impact the psychosocial aspects of quality of life. Onychomycosis treatment, especially topical, is long-term, and adequate follow-up is essential for cure. However, the realities and issues of patient-physician communication after treatment initiation, including patients' perception of efficacy, treatment satisfaction, and reconsideration of the treatment approach, remain unclear. Therefore, this study aimed to examine the realities and issues associated with onychomycosis treatment, focusing on topical therapies, through a web-based survey of patients with onychomycosis and dermatologists. The duration of topical treatment was prolonged, with 30.5% of patients undergoing topical therapy for more than 2 years. Of these, 54.5% had not perceived clear efficacy. In addition, 93.7% of all patients with onychomycosis expressed a desire to change their treatment if it was ineffective. However, only 29.9% of patients receiving topical treatment discussed changing their treatment with their physicians, and only 7.3% ultimately changed their treatment. These findings indicate that the review of treatment strategies was insufficient. Furthermore, the satisfaction rate among patients treated with oral medications was higher than that of patients treated with topical medication. Despite dermatologists' awareness of low patient satisfaction with topical treatments, approximately 40% recommended alternative topical therapies when the initial topical treatment was ineffective. These results suggest clinical inertia in the treatment of onychomycosis stemming from a lack of appropriate intensification of treatment. In managing onychomycosis, the patient and dermatologist must share a common understanding of the importance of regular evaluation and the optimization of treatment regimens during treatment and must work side by side toward a cure.

Wildlife as Reservoirs of Encephalitozoon Cuniculi and Encephalitozoon Hellem and Molecular Genotyping of Encephalitozoon spp. in Small Mammals in the Czech Republic.

Parasites of genus Encephalitozoon are well known pathogens of domestic animals however less attention was paid to its spread among wildlife that can play an important role of reservoir of infection. The aim of the study was to conduct molecular detection and genotype characterization of Encephalitozoon spp. in wild small mammals trapped in localities both near to and at a large distance from residential areas. In total, 300 wild small mammals (274 Rodentia and 26 Eulipotyphla) were trapped in 41 localities of the Czech Republic and tested by nested PCR for Encephalitozoon spp. The DNA of Encephalitozoon spp. was proved in tissues (brain or liver) of 11% (32/300) of animals. There was a statistically significant difference (p < 0.001) in positivity among animal species with the most infected species Micromys minutus (50%, 4/8) and Myodes glareolus (17%, 9/53). There was also statistically significant difference (p < 0.001) between localities with the higher positivity (29%, 12/42) in localities near to residential areas, compared to localities with a large distance from residential areas (8%, 20/258). Sex and age of wild small mammals did not have effect on their positivity. Genotyping analysis revealed E. cuniculi genotype II in 22 samples and E. hellem genotype 1A in one sample. This study brings new information on the molecular characterization of Encephalitozoon spp. isolated from wild small mammals trapped in two different areas (localities in near to residential areas and localities with a large distance from residential areas).

High chytrid prevalence and infection intensities in tadpoles of Mixophyes fleayi

Context The amphibian chytrid fungus Batrachochytrium dendrobatidis (Bd) has caused catastrophic biodiversity loss globally, but species and life stages within species respond differently to the pathogen. Although tadpoles are often reported to be less vulnerable to disease, they can constitute important infection reservoirs in ecosystems. Aims We aimed to describe Bd infection patterns of a long-lived tadpole in a species where post-metamorphic animals appear to exhibit limited mortality as a result of chytridiomycosis. We further investigated how oral dekeratinisation can be used as an indicator of infection. Methods We conducted surveys of tadpoles of Mixophyes fleayi (Fleay’s barred frog) over 2 years, at two rainforest streams on the east coast of Australia, to assess patterns in Bd infection prevalence and intensity. We developed an integrated hierarchical model propagating pathogen-detection errors and incorporating how Bd infections affect oral dekeratinisation. Key results We found that Bd infection prevalence was strongly associated with lower temperatures and a larger body size, consistent with Bd optimal thermal range and a cumulative risk of exposure for tadpoles. The individual probability of a tadpole being infected with Bd was estimated to be 0.58 [95% HPDI: 0.432, 0.713], the odds of which were approximately eight times greater than for adults at the same sites. Tadpoles infected with Bd were 113 [29, 293] times more likely to have oral dekeratinisation than were uninfected tadpoles, where uninfected individuals were estimated to have a 0.05 [95% HPDI: 0.011, 0.11] probability of having mouthpart loss. Conclusions Our results showed that M. fleayi tadpoles are more likely to be infected with Bd than are adults, suggesting that tadpoles could contribute to Bd maintenance in streams. We further showed that sites can be rapidly assessed for Bd by visually checking for oral dekeratinisation. Implications Long-lived tadpoles, in general, may contribute to Bd maintenance in ecosystems. We suggest continued exploration of Bd immunocompetence across amphibian life stages to further understand the vastly different infection patterns.

Molecular Testing of Environmental Samples as a Potential Source to Estimate Parasite Infection.

We discuss the potential usefulness of molecular testing of soil, dust, and water samples to detect medically important parasites, and where such testing could be used to supplement stool sampling in humans. A wide variety of parasites including protozoa and helminths, many of which are zoonotic, have an important infection reservoir in the environment. In some cases, this environmental period is essential for further parasite development. We describe the progress in implementing methods for the molecular detection of these parasites in soil across eight collaborating centers in Latin America and represent a variety of potential applications in improving our understanding of parasite epidemiology and mapping, surveillance, and control of these parasites. This methodology offers new opportunities for improving our understanding of a wide variety of parasites of public health importance and novel tools for their control.

Carbapenem-Resistant Enterobacter hormaechei Uses Mucus Metabolism to Facilitate Gastrointestinal Colonization.

Bloodstream infections caused by Enterobacter species pose a significant clinical threat. The intestine acts as the primary site for colonization and serves as a reservoir for infection. To combat this pathogen, it is crucial to understand how carbapenem-resistant Enterobacter species colonize the gut, as such knowledge can pave the way for alternative therapeutic targets. In this study, we developed a novel neonatal mouse model for gastrointestinal colonization by Enterobacter species and discovered that mucus plays a key role as a carbon source during colonization. Additionally, we identified two mucus catabolism pathways that contribute to intestinal colonization by carbapenem-resistant E. hormaechei. This new mouse model offers valuable insights into host-pathogen interactions and helps identify critical gastrointestinal fitness factors of Enterobacter, potentially guiding the development of vaccines and alternative therapeutic strategies to minimize intestinal carriage in patient populations at risk for infection with Enterobacter species.

Conjugation of anti-HIV gp41 monoclonal antibody to a drug capable of targeting resting lymphocytes produces an effective cytotoxic anti-HIV immunoconjugate.

HIV-infected cells persisting in the face of suppressive antiretroviral therapy are the barrier to curing infection. Cytotoxic immunoconjugates targeted to HIV antigens on the cell surface may clear these cells. We showed efficacy in mouse and macaque models using immunotoxins, but immunogenicity blunted the effect. As an alternative, we propose antibody drug conjugates (ADCs), as used in cancer immunotherapy. In cancer, the target is a dividing cell, whereas it may not be in HIV. We screened cytotoxic drugs on human primary cells and cell lines. An anthracycline derivative, PNU-159682 (PNU), was highly cytotoxic to both proliferating and resting cells. Human anti-gp41 mAb 7B2 was conjugated to ricin A chain or PNU. The conjugates were tested in vitro for cytotoxic efficacy and anti-viral effect, and in vivo for tolerability. The specificity of killing for both conjugates was demonstrated on Env+ and Env- cells. The toxin conjugate was more potent and killed more rapidly, but 7B2-PNU was effective at levels achievable in patients. The ricin conjugate was well tolerated in mice; 7B2-PNU was toxic when administered intraperitoneally but was tolerated intravenously. We have produced an ADC with potential to target the persistent HIV reservoir in both dividing and non-dividing cells while avoiding immunogenicity. Cytotoxic anti-HIV immunoconjugates may have greatest utility as part of an "activate and purge" regimen, involving viral activation in the reservoir. This is a unique comparison of an immunotoxin and ADC targeted by the same antibody and tested in the same systems.IMPORTANCEHIV infection can be controlled with anti-retroviral therapy, but it cannot be cured. Despite years of therapy that suppresses HIV, patients again become viremic shortly after discontinuing treatment. A long-lived population of memory T cells retain the genes encoding HIV, and these cells secrete infectious HIV when no longer suppressed by therapy. This is the persistent reservoir of HIV infection. The therapies described here use anti-HIV antibodies conjugated to poisons to kill the cells in this reservoir. These poisons may be of several types, including protein toxins (immunotoxins) or anti-cancer drugs (antibody drug conjugates, ADCs). We have previously shown that an anti-HIV immunotoxin had therapeutic effects in animal models, but it elicited an anti-drug immune response. Here, we have prepared an anti-HIV ADC, which would be less likely to provoke an immune response, and show its potential for use in eliminating the persistent reservoir of HIV infection.

Co-Designing Digital Health Intervention for Monitoring Medication and Consultation Among Transgender People in Underserved Communities: Collaborative Approach.

In many parts of the world, men who have sex with men and transgender individuals face criminalization and discrimination. As a result, they are less likely to seek medical help, despite experiencing higher rates of HIV/AIDS, mental health issues, and other health problems. Reaching key populations (KPs) with essential testing, care, and treatment services can be challenging, as they often have a higher likelihood of contracting and spreading the virus. They have limited access to antiretroviral (ARV) therapy (ART) services, which means that KPs may continue to serve as reservoirs for new HIV infections if they do not receive effective HIV programming. This ongoing issue complicates efforts to control the epidemic. Therefore, modeling a digital health system to track ARV medication access and use is crucial. This paper advocates for the use of digital interventions to manage the health of KPs in underserved regions, using Nigeria as a case study. This study aims to assess digital health interventions for monitoring medication and consultations among transgender people in underserved communities. It also sought to determine whether a system exists that could support ART adherence in Nigeria. Additionally, the study evaluated design strategies to address privacy and confidentiality concerns, aiming to reduce nonadherence to ARV medications among KPs in Nigeria. A qualitative approach was adopted for this research, involving a thematic analysis of information collected from interviews with clinicians and other health practitioners who work directly with these communities, as well as from an interactive (virtual) workshop. The findings from the thematic analysis indicate a need to increase attendance at ART therapy sessions through the implementation of an intensive care web app. Unlike previous solutions, this study highlights the importance of incorporating a reminder feature that integrates with an in-app telemedicine consultancy platform. This platform would facilitate discussions about client challenges, such as adverse drug effects, counseling sessions with clinical psychologists, and the impact of identity discrimination on mental health. Other data-driven health needs identified in the study are unique drug request nodes, client-led viral load calculators, remote requests, and drug delivery features within the web app. Participants also emphasized the importance of monitoring medication compliance and incorporating user feedback mechanisms, such as ratings and encouragement symbols (eg, stars, checkmarks), to motivate adherence. The study concludes that technology-driven solutions could enhance ART adherence and reduce HIV transmission among transgender people. It also recommends that local governments and international organizations collaborate and invest in health management services that prioritize health needs over identity.

ANTICIPATING BIOSECURITY HAZARDS: DISTRIBUTION AND RECOGNITION OF BIOLOGICAL THREATS

Understanding the potential biological weapons that can be created, the technologies involved, and the entities capable of producing them is crucial for biosecurity. Equally important is comprehending the various targets a biological weapon might be aimed at, the deployment methods, and available detection strategies to counteract illegal biological threats. This chapter delves into these aspects, starting with methods of deployment. The Center for Disease Control and Prevention (CDC) categorizes disease transmission into direct and indirect modes. Direct transmission involves contact with an infected person or environmental reservoir, including droplet spread, proven highly effective in densely populated areas. Indirect transmission occurs through contaminated objects or vectors. Vehicle-based transmission involves contaminating inanimate objects like food, water, and biological products. Vector-based transmission involves organisms carrying and transmitting pathogens. Airborne transmission, receiving significant attention for its potential in biological attacks, involves pathogens suspended in the air, posing significant risks, especially in crowded areas. Biological weapons could target humans, agriculture, technology, and the environment. Attacks on humans, often the focus of biosecurity efforts, pose catastrophic outcomes. State-sponsored programs often focus on human pathogens like Bacillus anthracis and Yersinia pestis. Agroterrorism, targeting agriculture and livestock, can lead to economic losses and social instability. Attacks on technology, utilizing synthetic biology, have shown the potential to manipulate DNA to store and deploy malicious code, highlighting vulnerabilities in sequencing systems. While attacks on the environment remain theoretical, advancements in gene drives raise concerns about manipulating ecosystems. Effective biosecurity involves pre- and post-deployment screening techniques. Pre-deployment screening, particularly gene synthesis, focuses on preventing the acquisition of DNA fragments for weapon production. Current measures involve background checks and screening against pathogen lists, yet gaps exist, including inadequate international policies and the potential to hide malicious sequences within longer ones. Post-deployment detection relies on traditional molecular diagnostic methods, but synthetic pathogens may evade detection, necessitating ongoing advancements in detection techniques. Real-time sensors and biosensors offer promising avenues for quick and accurate pathogen recognition, although challenges remain in detecting novel pathogens against a natural background. In conclusion, understanding the range of biological weapons, their potential targets, deployment methods, and detection strategies is essential for effective biosecurity. Continued research and advancements in detection technologies are crucial to staying ahead of evolving biological threats, ensuring a safer and more secure future.

MOLECULAR AND MORPHOLOGICAL CHARACTERIZATION OF SARCOCYSTIS INFECTIONS IN THE MUSCLES OF GRAY WOLVES (CANIS LUPUS) FROM MINNESOTA SUGGEST THEY MAY SERVE AS RESERVOIRS FOR INFECTION IN DOMESTICATED DOGS.

Sarcocystis infections were found for the first time in the muscles of 3 of 3 gray wolves (Canis lupus) from Minnesota. Two kinds (thin-walled and thick-walled) of sarcocysts were detected, based on the appearance of the sarcocyst wall. In wolf 1, sarcocysts were thin-walled (<0.5 μm), and without any visible protrusions. Ultrastructurally, the sarcocyst wall was type 1a and identical to Sarcocystis svanai of the domestic dog (Canis familiaris). The second kind of sarcocyst, with a relatively thicker (>1 μm) sarcocyst wall, was detected in wolves 2 and 3. Ultrastructurally, the sarcocyst wall had undulating, pleomorphic villar protrusion of type 9c; these sarcocysts were identical to Sarcocystis caninum from the domestic dog. Molecularly, the 2 Sarcocystis species were characterized using 18S, 28S, COI, ITS-1, and rpoB genetic markers. All these markers showed 100% identity to either of the 2 species previously described from the domestic dog. The thick-walled sarococyst corresponded to Sarcocystis caninum, whereas the thin-walled sarcocyst corresponded to Sarcocystis svanai.

Enzymatically enhanced ultrastructure expansion microscopy unlocks expansion of in vitro Toxoplasma gondii cysts.

Toxoplasma gondii is an intracellular parasite capable of establishing long-term chronic infection in nearly all warm-blooded animals. During the chronic stage, parasites encapsulate to form cysts predominantly in neurons and skeletal muscle. Current anti-Toxoplasma drugs do not eradicate chronic parasites, leaving a reservoir of infection. The cyst is critical for disease transmission and pathology, yet it is harder to study, with the function of many chronic-stage proteins still unknown. Ultrastructure expansion microscopy, a new method to overcome the light microscopy's diffraction limit by physically expanding the sample, allowed in-depth studies of acute Toxoplasma infection. We show that Toxoplasma cysts resist expansion using standard protocol, but an additional enzymatic digestion with the mucinase StcE allows full expansion. This protocol offers new avenues for examining the chronic stage, including precise spatial organization of cyst-specific proteins, linking these locations to morphological structures, and detailed investigations of components of the durable cyst wall.

Bat Rabies in the Americas: Is Myotis the Main Ancestral Spreader?

The rabies virus (RABV) is the exclusive lyssavirus affecting both wild and domestic mammalian hosts in the Americas, including humans. Additionally, the Americas stand out as the sole region where bat rabies occurs. While carnivore rabies is being increasingly managed across the region, bats are emerging as significant reservoirs of RABV infection for humans and domestic animals. Knowledge of the bat species maintaining rabies and comprehending cross-species transmission (CST) and host shift processes are pivotal for directing surveillance as well as ecological research involving wildlife reservoir hosts. Prior research indicates that bat RABV CST is influenced by host genetic similarity and geographic overlap, reflecting host adaptation. In this study, we compiled and analyzed a comprehensive nucleoprotein gene dataset representing bat-borne RABV diversity in Argentina and the broader Americas using Bayesian phylogenetics. We examined the association between host genus and geography, finding both factors shaping the global phylogenetic structure. Utilizing a phylogeographic approach, we inferred CST and identified key bat hosts driving transmission. Consistent with CST determinants, we observed monophyletic/paraphyletic clustering of most bat genera in the RABV phylogeny, with stronger CST evidence between host genera of the same family. We further discuss Myotis as a potential ancestral spreader of much of RABV diversity.

&lt;i&gt;Citrus reticulata&lt;/i&gt; flavonoids as a valuable source for reducing meat-borne &lt;i&gt;Aeromonas hydrophila&lt;/i&gt;

Meat products are one of the nutritious diet options available to consumers. However, meat products have the potential to serve as a reservoir of food-borne infections, such as those caused by Aeromonas species, which pose a significant risk to public health. A total of 270 samples, 30 of each minced beef, meatball, beef burger, chicken nuggets, chicken pane, chicken burger, canned anchovy, canned mackerel, and canned sardine, were obtained from supermarkets in Aswan Province, Egypt, to analyze the occurrence and virulence features of Aeromonas hydrophila. Influence of Citrus reticulata peel extract on the A. hydrophila count and its virulence capacity after different marinating periods was also analyzed. The obtained results revealed that the Aeromonas counts ranged from 2.02±0.30 to 4.21±0.27 log10 CFU/g and 37% of the analyzed samples were contaminated with Aeromonas spp. The main strains discovered were A. hydrophila (13.3%), A. sobria (9.6%), A. caviae (7.4%), A. veronii (4%), and A. fluvialis (2.6%). It was found by polymerase chain reaction that all tested strains (n = 36) belonged to Aeromonas spp., and 89% were identified as A. hydrophila. In contrast, virulence genes aerolysin (aerA) and cytotoxic enterotoxin (act) were found in 61.1% and 50% of the tested isolates, respectively, with a wide range of antibacterial resistance. Additionally, the influence of Citrus reticulata peel extract on A. hydrophila counts at different marinating periods declined significantly with increased concentration without major changes in the sensory criteria.

Persistent carriage of subpatent Plasmodium falciparum parasites associated with clinical malaria in a low transmission area in Senegal

ObjectivesIn low malaria transmission areas, the elimination of the disease has been hampered partly by the existence of a reservoir of subpatent Plasmodium falciparum infections within communities. This reservoir, often undetected, serves as a source of parasites and contributes to ongoing transmission and clinical malaria cases. MethodsThis study, spanning a period of 9 years from June 2014 to December 2022, examined individual variations and long-term subpatent P. falciparum carriage in two matched cohorts of 44 individuals each living in Dielmo village in the Sudanian area of Senegal. Biannual blood samples, collected in June/July and December of each year, underwent P. falciparum diagnosis by quantitative polymerase chain reaction. QGIS and R analytical tools were used to map infections, assess the occurrence and clustering of subpatent and clinical P. falciparum infections, and determine the risk of infection in the vicinity of asymptomatic P. falciparum carriers. ResultsThe point frequency and long-term P. falciparum carriage were significantly higher among the quantitative polymerase chain reaction (qPCR) positive cohort compared to the negative cohort across the 16 cross-sectional surveys analyzed in this study (19.76% vs 10.99%, P-value <0.001). Asymptomatic carriage events in qPCR-positive group were 18.86 ± 1.72% and significantly greater (P-value = 0.001) than in the qPCR-negative group (11.32 ± 1.32%). The relative risk of P. falciparum infection or clinical malaria calculated with a 95% confidence interval significantly increased in the vicinity of infected individuals and was 1.44 (P-value = 0.53) and 2.64 (P-value = 0.04) when at least one individual in the direct (household) or indirect (block of households) vicinity is infected, respectively. The risk increased to 3.64 (P-value <0.001) if at least 1/5 of individuals in the indirect vicinity were P. falciparum-infected. ConclusionsThe study provides a detailed qualitative and quantitative analysis of the asymptomatic P. falciparum reservoir and its temporal and spatial dynamics within two subgroups of P. falciparum-infected and non-infected individuals in Dielmo village. It identified high-risk populations known as “hotpops” and hotspots that could be targeted by innovative interventions to accelerate the elimination of malaria in Dielmo village.

Cost and budget impact of mass drug administration compared to expanded school-based targeted preventive chemotherapy for soil-transmitted helminth control in Zamboanga Peninsula, the Philippines

School-based targeted preventive chemotherapy (PC), the primary strategy for soil-transmitted helminth (STH) control, typically focusing on primary schoolchildren, was expanded to secondary school students in the Philippines in 2016. This program still excludes adults, who may also suffer from considerable morbidity and can be a significant reservoir of infection. Mass drug administration (MDA), where the entire population is treated, would bring additional health benefits but will also increase implementation costs. The incremental cost of implementing MDA for STH control compared to expanded school-based targeted PC, however, is unknown. A cost survey was conducted in Zamboanga Peninsula region in 2021 to estimate the economic and financial cost of implementing MDA compared to the expanded school-based targeted PC from a government payer perspective. A budget impact analysis was conducted to estimate the financial cost to the government of implementing MDA over a five-year timeframe. Monte Carlo simulation accounted for uncertainty in cost estimates. Costs were reported in 2021 United States Dollars ($). The economic cost of MDA was $809,000 per year (95% CI: $679,000-$950,000) or $0.22 per person targeted (95% CI: $0.19-$0.26), while the expanded school-based targeted PC would cost $625,000 (95% CI: $549,000-$706,000) or $0.57 per person targeted (95% CI: $0.50-$0.64). Over five years, the financial cost to the government for MDA would be $3,113,000 (95% CI: $2,475,000-$3,810,000); $740,000 (95% CI: $486,000-$1,019,000) higher than expanded school-based targeted PC. Implementing MDA in the region will increase the economic and financial costs by 29% and 31%, respectively, when compared to expanded school-based targeted PC. Implementing MDA would require the Department of Health to increase their total expenditure for STH control by 0.2% and could be key in addressing the ongoing STH burden. The project was funded by the Australian Centre for the Control and Elimination of Neglected Tropical Diseases (NHMRC GA19028), and JPCDT was supported by a UNSW Scientia PhD Scholarship. SVN is funded by an NHMRC Investigator Grant (APP 2018220).

The epizootic situation of bovine paratuberculosis in Ukraine for the period 2019–2023

Paratuberculosis (Johne’s disease) is a contagious infectious disease, the etiological agent of which affects various species of mammals, mainly ruminants. The causative agent is the acid-resistant bacterium Mycobacterium avium subsp. paratuberculosis (MAP), which belongs to the family Mycobacteriaceae. The most sensitive to it are domestic ruminants (cattle, sheep, goats etc.), which are the main reservoirs of infection for the various species of animals and humans (the zoonotic potential of the pathogen requires further study). In Ukraine, the main methods for diagnosing paratuberculosis are serological and bacteriological techniques. The authors analyzed the epizootic situation of paratuberculosis among cattle in Ukraine during 2019–2023 by systematizing the data of their own research and official reports of state veterinary laboratories in regions. The results of the investigation are presented without taking into account the temporarily occupied territories of Luhansk and Donetsk oblasts and the Autonomous Republic of Crimea, as well as part of the territory where military operations were conducted. In total, over the five-year period, 41 679 samples were examined serologically in the complement fixation test and 13 405 – bacteriologically, by microscopy and cultivation of biological materials on the nutrient media. During the investigation, specific antibodies to the pathogen were detected in 36 samples (prevalence, about 0.1%; BCI, 0.06–0.12%) from the ten regions. The analysis of the serological studies shows that the disease is sporadic and has a significant downward trend in the number of positive cases (17 positive samples were detected in 2019 and 2020, and only two in 2023). As for bacteriological examination, no positive cases have been registered during the 5-year period. In addition to the scrupulous work of the veterinary medicine service, both the persistent decrease in the cattle population and the ongoing hostilities in Ukraine have a considerable impact on improving the epizootic situation., as the number of serological tests conducted after 2022 has almost halved (especially in the eastern and southern regions), and bacteriological tests have decreased fivefold. The visualization of the data shows that antibodies were mostly detected in animals from the central, eastern, northern, and northwestern regions of the country.

CSF1R inhibition by PLX5622 reduces pulmonary fungal infection by depleting MHCIIhi interstitial lung macrophages

PLX5622 is a small molecular inhibitor of the CSF1 receptor (CSF1R) and is widely used to deplete macrophages within the central nervous system (CNS). We investigated the impact of PLX5622 treatment in wild-type C57BL/6 mice and discovered that one-week treatment with PLX5622 was sufficient to deplete interstitial macrophages in the lung and brain-infiltrating Ly6Clow patrolling monocytes, in addition to CNS-resident macrophages. These cell types were previously indicated to act as infection reservoirs for the pathogenic fungus Cryptococcus neoformans. We found that PLX5622-treated mice had significantly reduced fungal lung infection and reduced extrapulmonary dissemination to the CNS but not to the spleen or liver. Fungal lung infection mapped to MHCIIhi interstitial lung macrophages, which underwent significant expansion during infection following monocyte replenishment and not local division. Although PLX5622 depleted CNS infiltrating patrolling monocytes, these cells did not accumulate in the fungal-infected CNS following pulmonary infection. In addition, Nr4a1-deficient mice, which lack patrolling monocytes, had similar control and dissemination of C. neoformans infection to wild-type controls. PLX5622 did not directly affect CD4 T-cell responses, or significantly affect production of antibody in the lung during infection. However, we found that mice lacking lymphocytes had reduced numbers of MHCIIhi interstitial macrophages in the lung, which correlated with reduced infection load. Accordingly, PLX5622 treatment did not alter fungal burdens in the lungs of lymphocyte-deficient mice. Our data demonstrate that PLX5622 may help reduce lung burden of pathogenic fungi that utilise CSF1R-dependent myeloid cells as infection reservoirs, an effect which is dependent on the presence of lymphocytes.

Infection of human organoids supports an intestinal niche for Chlamydia trachomatis.

Several reports suggest that intestinal tissue may be a natural niche for Chlamydia trachomatis infection and a reservoir for persistent infections in the human body. Due to the human specificity of the pathogen and the lack of suitable host models, there is limited knowledge on this topic. In our study, we modelled the course of the chlamydial infection in human primary gastrointestinal (GI) epithelial cells originating from patient-derived organoids. We show that GI cells are resistant to apical infection and C. trachomatis needs access to the basolateral membrane to establish an infection. Transmission electron microscopy analysis reveals the presence of both normal as well as aberrant chlamydial developmental forms in the infected cells, suggesting a possible cell-type specific nature of the infection. Furthermore, we show that the plasmid-encoded Pgp3 is an important virulence factor for the infection of human GI cells. This is the first report of C. trachomatis infection in human primary intestinal epithelial cells supporting a possible niche for chlamydial infection in the human intestinal tissue.