Strep contagious for how long
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Duration of Contagiousness of Streptococcus Infections
Introduction to Streptococcus Infections
Streptococcus infections, particularly those affecting the udder in dairy herds, are a significant concern due to their contagious nature and potential to cause persistent infections. Understanding the duration of contagiousness is crucial for effective management and control of these infections.
Contagious Period of Streptococcus uberis
Streptococcus uberis is a common pathogen responsible for mastitis in dairy cows. During an outbreak, the contagious period can be influenced by several factors, including the number of existing infections and the phase of the outbreak. In a study conducted on a Dutch dairy farm, it was observed that the incidence of new infections was higher in quarters that had previously recovered from Strep. uberis infections. The study suggested that contagious transmission played a significant role during the outbreak period, which lasted for approximately 21 weeks1.
Persistent Infections by Streptococcus canis
Streptococcus canis, although less common, can establish persistent infections in dairy herds. A 15-month observation of subclinical Strep. canis mastitis revealed that the pathogen could cause long-duration intramammary infections. The study indicated that persistently infected cows could serve as a source of infection for other animals, behaving in a contagious manner similar to Streptococcus agalactiae. This suggests that control measures for Strep. canis should be as stringent as those for other more common Streptococcus species2.
Transmission Dynamics of Streptococcus agalactiae
Streptococcus agalactiae is another significant pathogen in dairy herds, known for its contagious nature. A study on a Dutch dairy herd using an automatic milking system (AMS) estimated the median duration of intramammary infections (IMI) caused by Strep. agalactiae to be around 86 days. The study also found that the transmission rate of Strep. agalactiae was slightly higher in AMS herds compared to conventional milking systems (CMS). Despite this, the basic reproduction number (R0) was lower than 1, indicating that the infection would not sustain in the herd without new introductions3.
Conclusion
The duration of contagiousness for Streptococcus infections in dairy herds varies depending on the specific pathogen and the conditions of the herd. Strep. uberis can cause outbreaks lasting several weeks, while Strep. canis can lead to persistent infections over months. Strep. agalactiae, although highly contagious, has a median infection duration of about 86 days, with transmission rates that can be managed effectively with proper control measures. Understanding these dynamics is essential for implementing effective strategies to control and prevent the spread of these infections in dairy herds.
Sources and full results
Most relevant research papers on this topic
Analysis of an outbreak of Streptococcus uberis mastitis.
Contagious transmission may have played a role in this outbreak of Strep. uberis mastitis in a Dutch dairy farm with good udder health management.
Observational Study
Highly CitedShort communication: Streptococcus canis is able to establish a persistent udder infection in a dairy herd.
Streptococcus canis can cause persistent udder infections in dairy herds, acting as a contagious source, and effective control may require similar measures to those used in Streptococcus agalactiae eradication programs.
Observational Study
Rigorous JournalTransmission dynamics of Staphylococcus aureus and Streptococcus agalactiae in a Dutch dairy herd using an automatic milking system.
Dutch dairy herds using automatic milking systems have comparable transmission rates of Staph. aureus and Strep. agalactiae, but slightly higher Strep. agalactiae transmission rates and lower R0 of these pathogens compared to conventional milking systems.
Comparison of transmission dynamics between Streptococcus uberis and Streptococcus agalactiae intramammary infections.
Strep. agalactiae has a longer duration of infection than Strep. uberis, suggesting a different transmission dynamic between the two pathogens in dairy herds.
Observational StudyRigorous JournalStreptococcus dysgalactiae—Contagious or Environmental?
Streptococcus dysgalactiae infections in cattle can occur via various routes, with some farms showing a single strain responsible for all cases, while others show multiple strains in mastitis milk within 14 months.
Observational StudyRigorous JournalGenotyping and Antimicrobial Susceptibility Profiling of Streptococcus uberis Isolated from a Clinical Bovine Mastitis Outbreak in a Dairy Farm
Strep. uberis strains from an Italian dairy farm showed low prevalence of -lactam resistance, with lincomycin (93%), tetracycline (85-8.9%), and one isolate showing resistance to six antimicrobial classes, including cephalosporins.
Observational StudyStrain diversity and infection durations of Staphylococcus spp. and Streptococcus spp. causing intramammary infections in dairy cows.
Staphylococcus epidermidis and Staph. haemolyticus infections in dairy cows have short durations, questioning the need for antimicrobial treatment for these organisms.
Observational StudyGroup B streptococcal disease in UK and Irish infants younger than 90 days, 2014-15: a prospective surveillance study.
The incidence of invasive group B streptococcal disease in infants younger than 90 days in the UK and Ireland has increased, with early-onset disease not declining despite national prevention guidelines.
Observational StudyRigorous JournalHighly CitedHospital clusters of invasive Group B Streptococcal disease: a systematic review.
Long intervals between cases in hospital clusters of invasive Group B Streptococcal disease may hinder detection of outbreaks without enhanced surveillance supported by genomics.
Systematic ReviewRigorous JournalComparison of Virulence Patterns Between Streptococcus uberis Causing Transient and Persistent Intramammary Infection
Streptococcus uberis strains show high similarity in virulence patterns regardless of transient or persistent intramammary infection, with few changes related to its subsequently changing to transient IMI.
Non-RCT
Animal Study