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Additional Information about Infectious Diseases
Published in Lyle D. Broemeling, Bayesian Analysis of Infectious Diseases, 2021
The aim of this chapter is to describe the statistical analysis of observational information of the behavior of infectious diseases. A disease is infectious if the infected host transitions through an infectious period, during which the person is capable of passing the disease to a susceptible individual, either by direct contact or by infecting the surrounding environment in such a way that the person becomes infected. Another way for a person to contract a disease is by an intermediate vector, that is, the disease is carried by the vector which subsequently infects the host. For example, a mosquito which has malaria transmits the disease to another by biting the victim. The infected immediate surroundings might include linen and utensils of a household or the ambient air in the house.
Markov Chain Monte Carlo Methods for Outbreak Data
Published in Leonhard Held, Niel Hens, Philip O’Neill, Jacco Wallinga, Handbook of Infectious Disease Data Analysis, 2019
Philip D. O’Neill, Theodore Kypraios
These data have been considered by a number of authors using different epidemic models of varying complexity. Here, for illustration, we consider the following model taken from [4]. Label the individuals . Each individual belongs to a household and the community, and either attends school or is of pre-school age. If an individual becomes infected, they undergo a symptom-free infectious period which is assumed to follow a distribution, where is fixed and δ is a model parameter. The value is largely chosen for illustration, but such a value means that the coefficient of variation of the symptom-free period is , meaning that we do not allow much relative variability. As in the previous discussion of latent periods, it would be hard to estimate both ω and δ separately, so fixing one parameter is also pragmatic. At the end of the symptom-free period, the individual displays symptoms and subsequently develops a rash. Both the symptom and rash appearance dates are given by the data and so we do not model the times of these events. Following the rash appearance, the individual is assumed to be recover 3 days later, unless they die first as indicated by the data. An individual is thus removed at either recovery or death, if sooner. The infectious period is assumed to start immediately after initial infection and continue until removal or death.
Genital ulcers and blisters
Published in Manu Shah, Ariyaratne de Silva, The Male Genitalia, 2018
Manu Shah, Ariyaratne de Silva
Around 70% of infected individuals may be asymptomatic. The diagnosis may only come to light when their partner displays symptoms. Sexually acquired herpes simplex occurs on the genitals within 7 days of exposure. Prior to the development of lesions, prodromal symptoms such as fever, headache and myalgia or local soreness may be experienced. Small vesicles then occur, most commonly on the glans penis and/or the foreskin. These are around 2–3mm in diameter on an erythematous base. Lesions may also be found on the thighs and buttocks. The usual symptoms are of local soreness and pain. Urethritis occurs in approximately 40% of affected men. Healing, initially with crusting, takes place after around 5–15 days. The median period of viral shedding (infectious period) is 12 days. Healing may result in skin changes of post-inflammatory hypo- or hyper-pigmentation.
Guidance for the pharmacological management of COVID-19 in the emergency setting
Published in Expert Opinion on Pharmacotherapy, 2022
Mohamad-Hani Temsah, Muneera Al-Jelaify, Ziad A Memish
During this pandemic the pharmacological management of COVID-19 continued to evolve, from management based on observational data ranging from anecdotes and case series to evidence-based management based on well-powered randomized clinical trials. The role of regulatory agencies is critical in pandemics to ensure the proper oversight and rapid approval process of new diagnostics and therapeutics. EUAs are important for providing clinicians with access to investigational products that cannot otherwise be prescribed. Updated and living guidelines from related societies are warranted. The most exciting data on novel COVID-19 therapeutics recently emerged with the development of new oral antivirals which if administered early in the disease course in patient at high risk of progression to severe diseases can reduce hospitalization and death. The actual potential of a treatment intervention to limit spread of the disease is rather limited (precisely, expressed as components of R0), it is only by potentially shortening the infectious period or reducing the probability of transmission per contact – and for SARS-CoV-2 all existing treatments have been shown to have close to zero effect on either. The concern with the COVID-19 is the continuous emergence of variants which could limit the effectiveness of some of the available therapeutics. Continuous surveillance and vigilance are needed to ensure early detection of these variants and prevent their spread.
An infant of 26 weeks gestation with congenital miliary tuberculosis complicated by chronic lung disease requiring CPAP was diagnosed on Day 104 of life: congenital tuberculosis was confirmed by detection of calcified ovaries in his mother
Published in Paediatrics and International Child Health, 2022
Akina Matsuda, Naoto Nishizaki, Hanako Abe, Akira Mizutani, Takahiro Niizuma, Kaoru Obinata, Kyoko Oguma, Shintaro Makino, Makoto Ishitate, Toshiaki Shimizu
The infectious period was defined as 3 weeks from the patient’s date of birth to the date of isolation. Exposed infants were defined as infants who were in the NICU with the index case during the infectious period. In total, 37 infants were exposed, and all tested negative for mycobacteria on a Mantoux tuberculin skin test. In accordance with the latest edition of the Handbook for Paediatric TB Care in Japan (3rd edition), they continued to receive oral isoniazid (10 mg/kg/day) and vitamin B6 supplementation (10 mg/kg/day) for 3 months to prevent peripheral neuropathy. At the 12-month follow-up, none of the exposed infants had developed TB. The IGRA of the exposed medical staff in the NICU (n=97) yielded negative results when tested twice every 8 weeks, and all were negative after 18 months.
Disciplining sexual and reproductive behaviour of tuberculosis patients in Bangladesh: a mixed method study exploring divergent messages
Published in Sexual and Reproductive Health Matters, 2022
Mrittika Barua, Francien van Driel
It is crucial to note here, however, that it can be challenging to achieve correctness and consistency in information when there is already confusion in the guidelines, as well as in the literature, regarding how long a person remains infectious after beginning treatment.19 While the Centers for Disease Control and Prevention (CDC), one of the top-level international organisations that work with tuberculosis, deems the infectious period to be two to three weeks,27 another study states that the infectious period may extend beyond this duration.28 The difficulty in determining a definite period of infectiousness is that the conversion of sputum from positive to negative takes place differently in different people.29 If the sputum test is the indicator for infectiousness, then this information should appear consistently in all documents and be disseminated to all patients. Since the treatment duration is long, it should also be assured that patients are informed if they are no longer infectious, as this would affect how soon an infected person can go back to close physical contact with other household members without putting them at risk of infection.