Tafenoquine as Treatment for Relapsing Babesiosis

This study evaluates the effectiveness of tafenoquine (antimalarial primaquine analog) for treatment in an immunocompromised patient infected by a strain of Babesia microti that was partially resistant to both azithromycin and atovaquone treatment. 

Tafenoquine received USDA approval in 2018 for use in only two indications: prophylaxis of malaria (for up to 6 months total) and prevention of relapse of Plasmodium vivax malaria. This drug has a relatively long half-life (14–17 days in humans), therefore a single dose can be administered once per week as an effective malaria prophylactic.

Tafenoquine has been found to be a highly effective treatment for B. microti infections in animal models. Three previous studies with hamsters/mice, including highly immunocompromised mice, demonstrated that tafenoquine effectively and rapidly cleared B. microti parasites from these hosts.

In this case study, an immunocompromised adult patient with multiple relapses of a B. microti infection was treated with a 6 week course of tafenoquine. This patient had previously failed treatment with both azithromycin and atovaquone, relapsing multiple times with babesiosis as documented through both clinical presentation (fevers, night sweats, chills, myalgias) and laboratory confirmation. Tafenoquine was well tolerated by the patient during treatment and over the course of follow-up, approximately 19 months. Additionally, the patient has remained well since treatment with tafenoquine. 

Because of the success witnessed in both animal models and this human case study, investigators indicate that this drug has a potential role in the treatment of patients with babesiosis, especially in patients who are highly immunocompromised and/or resistant to other therapies. They recommend that systematic clinical studies using tafenoquine be considered in other patients with babesiosis.

Read full text article here.

Read another article on Babesia treatment.

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Swedish Researchers Present New Findings on Immunization

According to a new study conducted by Swedish researchers at Lund University, the messenger RNA (mRNA) from Pfizer’s COVID-19 vaccine is able to enter human liver where it triggers the cell’s DNA, inside the nucleus, to increase the production of the LINE-1 gene expression to make mRNA. Results of the study showed rapid up-take of BNT162b2 (another name for Pfizer’s COVID-19 vaccine) in the human liver cell line Huh7 leading to changes in LINE-1 expression and distribution. Researchers additionally found that BNT162b2 mRNA is reverse transcribed within the cell into DNA within just 6 hours of exposure. 

Vaccine mRNA converting into DNA and being found inside the cell’s nucleus is a concern that the Centers for Disease Control and Prevention (CDC) addressed in their website post “Myths and Facts about COVID-19 Vaccines,” where they state, “The genetic material delivered by mRNA vaccines never enters the nucleus of your cells, which is where your DNA is kept.” Findings from this new study raise questions with this statement. 

Read full text study article here

Read the THE EPOCH TIMES news article here

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Western Blacklegged Ticks in Alaska: Modeling of Future Potential

In this article, researchers aimed to identify areas of potential suitable habitat for Ixodes pacificus (western blacklegged tick) within Alaska. Although not considered endemic, I. pacificus has been collected recently from domestic animals in Alaska. Questions remain regarding the ability for survival and reproduction in Alaska if this species is introduced to the high-latitude climate of Alaska.

Investigators used habitat modeling to calculate climatic and land vegetation cover variables in Alaska for both present conditions (1980–2014) and predicted future conditions (2070–2100). Suitability maps produced through this modelling show that both climate and land cover in Southeast Alaska and portions of Southcentral Alaska could support the establishment of I. pacificus populations, and that future forecasts show increased suitable habitat with much uncertainty for many areas of the state. Researchers suspect that repeated incidental introductions of this tick to Alaska increases the likelihood that this tick may become an established residential population in the future. 

Access to the Journal of Medical Entomology article can be found here

More LDA articles on western blacklegged ticks can be found here



Study Shows Potential for New Class of Antibiotics

new class of antibioticsACS Nano has published the results of a study demonstrating the link between human plasma and innate immunity and pointing at blood as a source of vital antimicrobials. Researchers examined three peptides sourced from the human apolipoprotein B (residues 887–922). In vitro and animal models found the peptides to be highly effective against the drug-resistant microbes, Klebsiella pneumoniaeAcinetobacter baumannii, and Staphylococci.

When used in combination, it was found that the peptides enhanced the use of conventional antibiotics without antimicrobial resistance. This recent discovery of encrypted peptides in the human proteome has potential to represent a new class of antibiotics.

Read the full study in ACS Nano.

NOTE from LDA: Borrelia Burgdorferi, one of the causative bacteria for Lyme disease, have not been shown to be resistant to antibiotics, but have been shown to be recalcitrant, perhaps due to biofilm formation. Read the article below.

Borrelia burgdorferi, the Causative Agent of Lyme Disease, Forms Drug-Tolerant Persister Cells

Overview of Several Difficult to Detect Gram-Negative Tick-Borne Pathogens

In this article published in FEMS Microbiology Reviews, researchers provide an overview of the current and future perspectives for diagnosis of several species of difficult to detect Gram-negative bacteria. Investigators discuss the zoonotic and vector-transmitted bacteria, Anaplasma spp., Bartonella spp., Coxiella burnetii, Orientia spp., and Rickettsia spp. These bacteria are strongly adapted to the infected host which impedes growth of these bacteria outside the host as well as identification of these pathogens. Because these bacterial species multiply slowly once they are removed from their host, it complicates the laboratory diagnosis of the disease. The slow growth of bacteria further hinders detection and characterization of the bacteria, and impacts resistance to antibiotic treatment. 

Authors summarize the existing diagnostic protocols for each of the bacteria investigated. They also identify specific limitations that exist for implementing novel diagnostic approaches and highlight the need for further optimizing or expanding the equipment, methods, and pharmaceuticals used in diagnostics and treatment. They discuss new technologies, including mass spectrometry, next generation nucleic acid sequencing, and in vitro diagnostic tools for potentially improved diagnostics of these difficult to detect and treat pathogens.

Read the full text article here

Read additional LDA articles on other tick-borne diseases here

Deer as Dilution Hosts for Lyme Pathogen?

In this study, investigators evaluated the potential for deer as zooprophylactic or “dilution” hosts for Borrelia burgdorferi in tick vectors. Zooprophylaxis is the diversion of vector bites from the reservoir host to other hosts. As deer are considered to be incompetent reservoirs of B. burgdorferi in the northeastern US, it was hypothesized that they may serve as “dilution” hosts if larvae of the blacklegged deer tick (Ixodes scapularis) frequently feed on them. 

Nymphal ticks, both Lone star ticks (Amblyomma americanum) and blacklegged ticks, were collected during the same sampling period at 4 study sites, which provided an index of the availability of deer in these sites. Blacklegged tick nymphs were found to have fed as larvae on a variety of hosts, including mice, birds and shrews, however blacklegged tick nymphs rarely fed on deer. Lone star tick nymphs, in contrast, commonly fed on deer.

In order to identify the host upon which larvae tick had fed, researchers used bloodmeal analysis on nymphal blacklegged ticks collected in the field. Findings were that Lone star ticks collected at the same time as blacklegged deer ticks commonly fed on deer, but blacklegged ticks did not. Researchers concluded that deer are not a preferred host for larval blacklegged ticks and therefore do not serve as dilution hosts. 

Access to full text article can be found here

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Review of Lyme in Prosthetic Joint Infections

This article summarizes a review of the literature regarding reported cases of prosthetic joint infections (PJI) caused by Lyme in knee replacements. The goal of the review was to initiate the development of a treatment strategy for these infections.

Investigators found only five cases of Lyme PJI in the literature after searching Scopus and PubMed published reports of cases of PJIs secondary to Lyme disease. All cases were from patients residing in the northeastern region of the US. All patients were successfully treated, 4 with surgical intervention and postoperative antibiotics and one with intravenous and oral antibiotics for 6 weeks, without surgical intervention. 

In all patient cases reviewed, synovial fluid Lyme polymerase chain reaction and serological tests were positive, and at the conclusion of treatment all patients were asymptomatic. 

Authors recommend practitioners in endemic regions highly consider Lyme disease infections in cases of PJI that are culture-negative. Authors further suggest that additional research is needed to clearly define an effective treatment regimen for these patients. 

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Read additional LDA articles regarding Lyme in tissues here

Seresto Dog Collar Proves Effective in Preventing TBD Transmission

Parasitology Research has published research findings on the effectiveness of the Seresto® (imidacloprid 10% + flumethrin 4.5%) dog collar in preventing transmission of both Borrelia burgdorferi and Anaplasma phagocytophilum. Effectiveness of the prevention collar was tested on dogs in two studies using naturally infected ticks. Each study consisted of a non-treated control group as well as a group treated with the Seresto® collar. All dogs were serologically tested for the presence of pathogens prior to study implementation.

The treated groups of dogs were fitted with Seresto® collars two months prior to tick infestations. All dogs were exposed to ticks that were naturally infected with B. burgdorferi and A. phagocytophilum. In study 1, two of six non-treated dogs became infected with B. burgdorferi, and four of six tested positive for A. phagocytophilum after being exposed to naturally infected Ixodes ricinus ticks. In study two, 10 of 10 non-treated dogs became infected with B. burgdorferi and A. phagocytophilum after being exposed to naturally infected Ixodes scapularis ticks. None of the treated dogs in either study tested positive for B. burgdorferi or A. phagocytophilum. Transmission of both pathogens was successfully blocked for up to 7 months on dogs wearing Seresto® collars.

Investigators reported that no serious treatment-related events were found with use of the Seresto® collar in the treated groups of dogs. Only mild signs of hair loss and skin irritation were observed, primarily in the group dogs treated for 7 months. The use of the acaricide collar showed 100% efficacy for killing ticks at 48 h for both tick species at time periods of 1, 2 and 7 months after the placement of the collar. 

Authors conclude that due to its long-term efficacy, the Seresto® collar may be a valuable tool in the prevention of tick pathogen transmission to dogs. 

NOTE: This article in presented for informational purposes only. The LDA does not recommend or endorse products. 

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Teasel for Treatment of Lyme?

In a recent Pharmaceuticals article, researchers continued the search for phytochemicals effective against resistant Lyme disease. The root of Dipsacus fullonum L., also known as wild teasel, is known as “Xu duan” in Chinese medicine and is recognized for both its anti-cancer and anti-inflammatory properties. As a promising plant source, investigators in this new study evaluated the activity of wild teasel leaves extract and its fractions against stationary phase B. burgdorferi in vitro.  

Two main classes of substances were identified in the study: polyphenols and iridoids. The two major polyphenols were saponarin and chlorogenic acid, the main iridoids were sylvestrosides III and IV, loganic acid and loganin.

Sylvestrosides III and IV bioactives showed effective anti-Borrelia activity in vitro, as well as proving to be least toxic to murine fibroblast NIH/3T3 cells. The concentration of sylvestrosides was about 15% of wild teasel extract, demonstrating the potential for purification of the compounds from wild teasel leaves. Wild teasel leaf extract has now been characterized as a potential source of anti-Borrelia bioactives. 

Previously, bioactives from wild teasel roots have exhibited minimal activity against Lyme disease, however studies have demonstrated the significant differences in composition of leaves from that of the root. Researchers have now found great potential for testing the bioactive sylvestrosides against the latent forms of B. burgdorferi as separate phytochemicals, as well as testing in combination with other bioactives, antibiotics and micronutrients to evaluate effectiveness against latent Lyme bacteria.

Access to full text article here

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Remnants of Lyme Bacteria Responsible for Ongoing Brain Inflammation?

A new study from Tulane researchers just published in Scientific Reports, demonstrates that remnants of the Lyme disease causing bacteria may contribute to ongoing inflammation in both the central and peripheral nervous systems even when bacteria is no longer viable. Researchers studied the B. burgdorferi (Bb) remnants on nervous system tissue using a nonhuman primate model looking at effects on both the frontal cortex and the dorsal root ganglion. Inflammatory markers found in these areas were significantly higher in samples exposed to remnants of B. burgdorferi than in samples exposed to live bacteria. Remnants were also significantly higher in the frontal cortex than the dorsal root ganglion and were found to also cause cell death in brain neurons. All of these impacts can cause serious long-term health consequences.

Researchers state that there remains uncertainty regarding how Bb spirochetes disseminate into the brain tissue, and that although antibiotics may kill the bacteria in these organs, remnants could remain and induce ongoing inflammation. Although these findings may explain some of the neurological symptoms and conditions that persist after a Lyme infection, authors stated that further studies are planned to explore and investigate both therapies for neuroinflammation as well as the mechanisms for why the body may not be able to clear bacteria or their remnants. 

Access to the full text article in Scientific Reports here

Read the Tulane News article here