Exogenous Spread Research Articles

Koala retrovirus infection and disease in South Australian koala (Phascolarctos cinereus) populations. In Proceedings of the Second Koala Retrovirus Workshop, ed. D. E. Alquezar-Planas, D. P. Higgins, C. L. Singleton, and A. D. Greenwood

Koala retrovirus (KoRV) infection, endogenous in all northern koalas (Phascolarctos cinereus), has been found to occur at lower, but increasing, prevalence in the Kangaroo Island and Mount Lofty Ranges koala populations in South Australia. Proviral and viral loads are also lower than in Queensland koalas, which may be due to exogenous spread of infection, or may be related to the variable presence of viral genes and fragmented expression that has been found in positive Mount Lofty Ranges koalas. However, high proviral loads and full expression across the KoRV genome in South Australian koalas has been found in individuals with neoplasia, particularly lymphoma, which can be as extensive and as severe as that observed in northern koalas. KoRV-A is the predominant subtype and no association with chlamydial status has been found except that high viral loads correlate with severity of chlamydiosis. Based on the complexity of KoRV infections in South Australian koalas, further research is needed to understand the differences in transmission and pathogenesis that occur.

Exo-SIR: an epidemiological model to analyze the impact of exogenous spread of infection.

Epidemics like Covid-19 and Ebola have impacted people’s lives significantly. The impact of mobility of people across the countries or states in the spread of epidemics has been significant. The spread of disease due to factors local to the population under consideration is termed the endogenous spread. The spread due to external factors like migration, mobility, etc., is called the exogenous spread. In this paper, we introduce the Exo-SIR model, an extension of the popular SIR model and a few variants of the model. The novelty in our model is that it captures both the exogenous and endogenous spread of the virus. First, we present an analytical study. Second, we simulate the Exo-SIR model with and without assuming contact network for the population. Third, we implement the Exo-SIR model on real datasets regarding Covid-19 and Ebola. We found that endogenous infection is influenced by exogenous infection. Furthermore, we found that the Exo-SIR model predicts the peak time better than the SIR model. Hence, the Exo-SIR model would be helpful for governments to plan policy interventions at the time of a pandemic.

Critical Analysis of Endophthalmitis in Ayurvedic View and Management of its Associated Symptoms Through Ayurveda - A Case Report

Endophthalmitis is a sight threatening inflammatory disorder of the eye which affects the uveal tissue, retina, vitreous, anterior chamber and posterior chamber. It occurs as a result of endogenous or exogenous spread of infecting organisms to the eye. The most commonly seen exogenous form of endophthalmitis are post-operative infection following intra ocular surgery and as a complication of perforated injury to infected corneal ulcer. Out of the infected corneal ulcer mycotic form is the most common variety. In severe conditions of endophthalmitis vision cannot be regained. Further management to control the infection is evisceration or enucleation. In Ayurveda there is similar condition which explained in two contexts. One is Paktya sukla in the context of Krishnagata roga and the other is Akshipakatyaya in the context of Sarvakshiroga. Pakatya sukla can be considered as exogenous origin of endophthalmitis due infected corneal ulcer and Akshipakatyaya as endogenous or systemic origin of endophthalmitis. Generally, the condition is considered as Asadhya but in the initial stages if it is not associated with severe pain the condition can be managed symptomatically with guarded visual prognosis. In this article the same concept is explored along with the details of a diagnosed case of endophthalmitis presented in regular OPD with associated pain, redness, discharge and photophobia. Diagnosed the case as Pakatyaya sukla and managed with drugs and procedures having Pitha samana, Rakta Prasadana properties and application of Jalooka. With the treatment duration of 15 days the associated symptoms resolved completely.

Phylogenetic and geographical analysis of a retrovirus during the early stages of endogenous adaptation and exogenous spread in a new host.

Most retroviral endogenization and host adaptation happened in the distant past, with the opportunity to study these processes as they occurred lost to time. An exception exists with the discovery that koala retrovirus (KoRV) has recently begun its endogenization into the koala (Phascolarctos cinereus) genome. What makes this opportunity remarkable is the fact that Northern Australian koalas appear to be undergoing endogenization with one KoRV subtype (KoRV‐A), while all subtypes (KoRV‐A‐I) coexist exogenously, and Southern Australian koalas appear to carry all KoRV subtypes as an exogenous virus. To understand the distribution and relationship of all KoRV variants in koalas, the proviral KoRV envelope gene receptor binding domain was assessed across the koala's natural range. Examination of KoRV subtype‐specific proviral copy numbers per cell found that KoRV‐A proviral integration levels were consistent with endogenous incorporation in Northern Australia (southeast Queensland and northeast New South Wales) while revealing lower levels of KoRV‐A proviral integration (suggestive of exogenous incorporation) in southern regions (southeast New South Wales and Victoria). Phylogeographical analysis indicated that several major KoRV‐A variants were distributed uniformly across the country, while non‐KoRV‐A variants appeared to have undergone lineage diversification in geographically distinct regions. Further analysis of the major KoRV‐A variants revealed a distinct shift in variant proportions in southeast New South Wales, suggesting this as the geographical region where KoRV‐A transitions from being predominantly endogenous to exogenous in Australian koalas. Collectively, these findings advance both our understanding of KoRV in koalas and of retroviral endogenization and diversification in general.

Route and Length of Therapy of Acute Uncomplicated Hematogenous Osteomyelitis: Do We Have the Answers Yet?

Acute hematogenous osteomyelitis (AHOM) is not uncommonly encountered in hospitalized pediatric patients, occurring in 1 in 5000 children per year or 1% of pediatric hospitalizations.1 There are published data regarding the length of antibiotic therapy, with many studies supporting an initial short intravenous (IV) course of therapy followed by an oral course of several weeks. Le Saux2 performed a systematic review that supported short-course IV therapy for AHOM. Peltola3 published the largest prospective study to date addressing treatment of AHOM, which supported short-course IV therapy followed by oral therapy for a total of 20 days. However, in practice, it is not so straightforward. It is not unusual for practitioners to recommend a long IV course of therapy, even in the face of an uncomplicated case of AHOM. Uncomplicated AHOM has been variably defined, but in general it would refer to osteomyelitis in a patient with <14 days of symptoms, no underlying medical conditions, and infection not associated with trauma and not requiring extensive surgical intervention3–6. This review synthesizes the available literature and addresses 2 clinical questions: (1) Is it reasonable to use short-course IV therapy in uncomplicated AHOM in pediatric patients? and (2) What is the appropriate total duration of therapy for uncomplicated AHOM in pediatric patients? AHOM is defined as <2 weeks of clinical symptoms with associated laboratory and imaging findings characteristic of AHOM and without any source for exogenous spread to the bone, such as may occur with penetrating trauma. The Pub Med and Google Scholar databases were used to conduct searches. Google Scholar was used to aid in finding open-access articles that might not be listed in PubMed. The search followed Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.7 Google scholar search terms included “osteomyelitis …

The microbiology of endophthalmitis: global trends and a local perspective

Endophthalmitis is a rare but frequently devastating infection, caused by diverse organisms, including bacteria, viruses, fungi, and parasites. The causative agents of endophthalmitis vary according to the mechanism. The involvement of intraocular structures can result from exogenous spread from ocular trauma, infection of adjacent structures, or as a complication of intraocular surgery. Of the causes of exogenous endophthalmitis, post-operative endophthalmitis is the most frequently encountered; specifically, cataract surgery is the most frequent eye surgery and, thus, leads the list of surgery-associated endophthalmitis. Exogenous source is far more common than endogenous endophthalmitis, a disease that is caused by the hematogenous spread of organisms from a remote infectious site to the eye, leading to severe visual loss. Several large series estimate that endogenous endophthalmitis accounts for 2-15% of all cases of endophthalmitis. Progressive vitritis is a hallmark for all forms of endophthalmitis, accompanied by intraocular inflammation, loss of vision, pain, and hypopyon. The common presentation consists of reduced vision, conjunctival injection, pain, and eyelid swelling. We reviewed the microbiology of endophthalmitis during a 9-year period in Winnipeg, Canada. Gram-positive bacteria with coagulase-negative staphylococci are the most common causative organisms, reflecting the association with surgical procedures.

Endogenous or exogenous spreading of HIV-1 in Nordrhein-Westfalen, Germany, investigated by phylodynamic analysis of the RESINA Study cohort

HIV's genetic instability means that sequence similarity can illuminate the underlying transmission network. Previous application of such methods to samples from the United Kingdom has suggested that as many as 86% of UK infections arose outside of the country, a conclusion contrary to usual patterns of disease spread. We investigated transmission networks in the Resina cohort, a 2,747 member sample from Nordrhein-Westfalen, Germany, sequenced at therapy start. Transmission networks were determined by thresholding the pairwise genetic distance in the pol gene at 96.8% identity. At first blush the results concurred with the UK studies. Closer examination revealed four large and growing transmission networks that encompassed all major transmission groups. One of these formed a supercluster containing 71% of the sex with men (MSM) subjects when the network was thresholded at levels roughly equivalent to those used in the UK studies, though methodological differences suggest that this threshold may be too generous in the current data. Examination of the endo- versus exogenesis hypothesis by testing whether infections that were exogenous to Cologne or to Dusseldorf were endogenous to the greater region supported endogenous spread in MSM subjects and exogenous spread in the endemic transmission group. In intravenous drug using group subjects, it depended on viral strain, with subtype B sequences appearing to have origin exogenous to the Resina data, while non-B sequences (primarily subtype A) were almost completely endogenous to their local community. These results suggest that, at least in Germany, the question of endogenous versus exogenous linkages depends on subject group.

Endogenous Endophthalmitis in the Developing World

IntroductionEndophthalmitis is a rare but potentially devastating intraocular infection that can result from exogenous spread after intraocular surgery, a complication of ocular trauma or from an adjacent ocular interface. A less common form of endophthalmitis; endogenous endophthalmitis is caused b

Bilateral endogenous endophthalmitis due to pseudomonas aeruginosa in a neonate.

Bacterial eye infections are rare in the neonatal population and usually come from exogenous spread. Eye infection due to Pseudomonas aeruginosa, although uncommon, may be a devastating disease, especially in premature infants. Retrospective review of the clinical chart of a 10-day-old newborn baby with bilateral endogenous Pseudomonas aeruginosa endophthalmitis. The patient presented with leukokoria in both eyes 7 days after the onset of severe septicemia due to endophthalmitis in both eyes. The baby received systemic treatment with meropenem and vancomycin, which the cultured bacteria were susceptible to, but the infection progressed. Intravitreal ceftazidime treatment and later vitrectomy could not prevent complete retina detachment and the progressive evolution to phthisis. Aggressive therapy including systemic antibiotics, intravitreous antibiotic injection, and vitrectomy could not prevent a poor outcome leading to retinal detachment and blindness in both eyes. A discussion of the treatment options and a review of the literature are also included.

Molecular epidemiology ofCandidaspecies isolated from clinical specimens of intensive care unit patients

Epidemiological analysis of nosocomial Candida infections has gained importance due to an increase in these infections during the recent years. This study investigated the prevalence of clinical infections of Candida in anesthesiology intensive care unit patients, and ascertains the level of genetic diversity in the Candida species. A total of 70 Candida isolates, consisting of 42 Candida albicans, 16 Candida glabrata and 12 Candida tropicalis strains isolated from various clinical sites of infection of anesthesiology intensive care unit patients, were analysed. The susceptibility of the isolates against amphotericin B and fluconazole was determined by microdilution method according to Clinical and Laboratory Standards Institute M27-A2 standards. The strains were typed by random amplified polymorphic DNA (RAPD)-PCR using OPE-03, OPE-18, RP4-2 and AP50-1 primers. In the patients with Candida infections, most isolates exhibited different RAPD patterns. Only three C. albicans pairs isolated within a short time period had the same RAPD pattern. Most of the Candida infections in the anesthesiology intensive care unit of our hospital seem to be caused by endogenous strains. Exogenous spread of C. albicans infections occurred less frequently.

Bacterial contamination in cerebrospinal fluid shunt surgery.

Infection is a major complication of cerebrospinal fluid (CSF) shunt treatment with a reported incidence of 8-27%. In the present study, comprising 64 patients operated under strictly defined preoperative and peroperative hygienic measures and without use of prophylactic antibiotics, the infection rate was 3.1%. Out of the 2 cases of shunt infection recorded, 1 was probably caused by peroperative contamination and 1 by postoperative, hematogenous spread. Bacterial cultures from the operation area before incision and during operation were negative in 95% and 78%, respectively, and when positive yielded low numbers of organisms. Specimens taken after skin closure revealed growth in 59% and high bacterial numbers in 20%, mostly of Staphylococcus epidermidis and other resident skin bacteria. In addition, cultures of irrigation solutions, kept in open bowls during operation, yielded bacterial growth in 65% with a predominance of S. epidermidis. Thus, the strict hygienic measures did not prevent bacterial recolonization of the wound during operation. It is conceivable that endogenous as well as exogenous spread may be of importance in this context. The contamination of irrigation solutions indicates that closed irrigation systems should be used in this type of surgery.

Characterization of an unusual strain of proteus rettgeri associated with an outbreak of nosocomial urinary-tract infection.

An outbreak of nosocomial urinary-tract infection was caused by a strain of Proteus rettgeri that fermented lactose overnight and was resistant to all antimicrobial drugs tested. The nonmotile isolates shared an O (somatic) antigen that differed from those of wild-type P. rettgeri. The organisms proved markedly serum-sensitive. In rats, the isolates elicited an acute interstitial nephritis with associated transient bacteriuria. Attempts to transfer the lac(+) trait and drug-resistance markers to recipient strains of Escherichia coli K-12 failed; exposure of the isolates to acridine orange yielded small numbers of non-lactose-fermenting variants which, however, were still as drug-resistant as before. Epidemiological studies failed to uncover the source of this unique strain and appeared to indicate exogenous spread of infection.

Characterization of an Unusual Strain of Proteus rettgeri Associated with an Outbreak of Nosocomial Urinary-Tract Infection

An outbreak of nosocomial urinary-tract infection was caused by a strain of Proteus rettgeri that fermented lactose overnight and was resistant to all antimicrobial drugs tested. The nonmotile isolates shared an O (somatic) antigen that differed from those of wild-type P. rettgeri. The organisms proved markedly serum-sensitive. In rats, the isolates elicited an acute interstitial nephritis with associated transient bacteriuria. Attempts to transfer the lac(+) trait and drug-resistance markers to recipient strains of Escherichia coli K-12 failed; exposure of the isolates to acridine orange yielded small numbers of non-lactose-fermenting variants which, however, were still as drug-resistant as before. Epidemiological studies failed to uncover the source of this unique strain and appeared to indicate exogenous spread of infection.