Epidemiological and clinical characteristics of a family cluster of psittacosis: A case report

Psittacosis accounts for 1-2 % of community-acquired pneumonia. In recent years, reports of psittacosis are increasing. Most reported cases of psittacosis are sporadic. Here, we report a familial cluster of five patients infected with Chlamydophila in a northwest Chinese region and share our diagnosis and treatment experience. The epidemiological characteristics, clinical features, laboratory examinations of family cluster psittacosis were collected and analyzed. We closely followed up all the family members and analyzed their clinical outcome. Five cases of family clustered pneumonia were mainly characterized by fever, cough and fatigue. mNGS rapidly identified the infecting agent as Chlamydophila in case 1 followed by RT-PCR analysis. A newly purchased pet parrot, which had diarrhea, was probably the primary source of infection. The main change of inflammation index in five patients was the decrease of lymphocyte counts. Chest CT showed peripheral or subpleural involvement of patchy high-density shadows with bronchial ventilation signs and blurred edges, mostly unilateral lesions. Five cases were completely cured with moxifloxacin and azithromycin. Our findings suggest that a familial cluster of Chlamydophila infection maybe caused by contact with sick pet parrot or human to human transmission in one close family. For this community-acquired pneumonia, epidemiological characteristics and use of mNGS is very important for improving accuracy in the early diagnosis.

The Role of Host in the Spectrum of Outcomes in Family Clusters of Hepatitis Infection: From Asymptomatic to Hepatocellular Carcinoma

Hepatitis B virus infections are prevalent worldwide, but the outcomes of infection vary greatly from host to host. In many endemic regions, vertical transmission from mother to child is most common. In this transmission setting, virus genotype and shared patient genetics make for an interesting comparison of outcome of chronic hepatitis B infection. This case series demonstrates four family clusters which display disparate outcomes among family members with hepatitis B virus infections, further stressing the role of host and non-genetic factors in the natural history of the disease. Many host factors have been theorized, from epigenetic mechanisms to the role of chronic stress, but more research is needed to better understand those at higher risk of feared complications such as hepatocellular carcinoma and cirrhosis.

Clinical characteristics of COVID-19 in family clusters: a systematic review

BACKGROUND

Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has spread around the world and reports of children during early epidemic period showed features of family clusters. The aim of this study is to assess clinical profiles of COVID-19 in family clusters with children.

METHODS

We performed a systematic literature review of English database (PubMed, Web of Science) and Chinese database (" www.cnki.net ", " www.cqvip.com " and " www.Wanfangdata.com.cn ") to identify papers on family clusters of COVID-19 with children and their family members.

RESULTS

Eighteen studies involving 34 children and 98 adults from 28 families were included. Fever, cough and ground-grass opacity change of chest computed tomography (CT) were the dominant features, whereas proportion of asymptomatic infections for children was higher than adults with statistical significance (32.4% and 13.3%, respectively, P < 0.05). Median time of longer incubation period (10 days) and shorter duration of pharyngeal swab nucleic acid test positive period (11 days) were seen in children than adults (7 and 17 days, respectively) with statistical significance (P < 0.05). There were statistically significant differences in lymphopenia, increased C-reactive protein and abnormal chest CT between children and adult patients (P < 0.05). Twenty-seven families reported adults as first case of COVID-19 in family clusters.

CONCLUSIONS

The same virus strain can cause milder disease in children compared with their caregivers. Children of COVID-19 were infected by adults in family during the early epidemic period. Asymptomatic patients can transmit the virus.

Clinical and epidemiological features of COVID-19 family clusters in Beijing, China

BACKGROUND

Since its discovery, SARS-CoV-2 has been spread throughout China before becoming a global pandemic. In Beijing, family clusters are the main mode of human-human transmission accounting for 57.6% of the total confirmed cases.

METHOD

We present the epidemiological and clinical features of the clusters of three large and one small families.

RESULT

Our results revealed that SARS-CoV-2 is transmitted quickly through contact with index case, and a total of 22/24 infections were observed. Among those infected, 20/22 had mild symptoms and only two had moderate to severe clinical manifestations. Children in the families generally showed milder symptoms. The incubation period varied from 2 to 13 days, and the shedding of virus from the upper respiratory tract lasted from 5 to over 30 days. A prolonged period of virus shedding (>30 days) in upper respiratory tract was observed in 6/24 cases.

CONCLUSION

SARS-CoV-2 is transmitted quickly in the form of family clusters. While the infection rate is high within the cluster, the disease manifestations, latent period, and virus shedding period varied greatly. We therefore recommend rigorously testing contacts even during the no-symptom phase and consider whether viral shedding has ceased before stopping isolation measures for an individual.

Familial MPN Predisposition

Chronic myeloproliferative neoplasms (MPN) characteristically arise from a somatic mutation in the pluripotent hematopoietic stem cell, and most common recurring mutations are in the JAK2, CALR, and cMPL genes. However, these mutations are not founder mutations, but mainly drive the disease phenotype and a pre-existing germline predisposition has been long speculated, but has not been clearly defined to date. Genome-wide association studies in family clusters of MPN have identified a number of genetic variants that are associated with increased germline risk for developing clonal MPN. The strongest association discovered so far is the presence of JAK2 46/1 haplotype, and subsequently, many studies have found additional variants in other genes, most notably in TERT gene. However, these still account for a small fraction of familial MPN, and more in-depth studies including whole genome sequencing are needed to gain better insight into familial genetic predisposition of clonal MPNs.

Epidemiological and virological differences in human clustered and sporadic infections with avian influenza A H7N9

BACKGROUND

Previous research has suggested that avian influenza A H7N9 has a greater potential pandemic risk than influenza A H5N1. This research investigated the difference in human clustered and sporadic cases of H7N9 virus and estimated the relative risk of clustered infections.

METHODS

Comparative epidemiology and virology studies were performed among 72 sporadic confirmed cases, 17 family clusters (FCs) caused by human-to-human transmission, and eight live bird market clusters (LCs) caused by co-exposure to the poultry environment.

RESULTS

The case fatality of FCs, LCs and sporadic cases (36%, 26%, and 29%, respectively) did not differ among the three groups (p>0.05). The average age (36 years, 60 years, and 58 years), co-morbidities (31%, 60%, and 54%), exposure to birds (72%, 100%, and 83%), and H7N9-positive rate (20%, 64%, and 35%) in FCs, LCs, and sporadic cases, respectively, differed significantly (p<0.05). These higher risks were associated with increased mortality. There was no difference between primary and secondary cases in LCs (p>0.05). However, exposure to a person with confirmed avian influenza A H7N9 (primary 12% vs. secondary 95%), history of visiting a live bird market (100% vs. 59%), multiple exposures (live bird exposure and human-to-human transmission history) (12% vs. 55%), and median days from onset to antiviral treatment (6 days vs. 3 days) differed significantly between primary and secondary cases in FCs (p<0.05). Mild cases were found in 6% of primary cases vs. 32% of secondary cases in FCs (p<0.05). Twenty-five isolates from the three groups showed 99.1-99.9% homology and increased human adaptation.

CONCLUSIONS

There was no statistical difference in the case fatality rate and limited transmission between FCs and LCs. However, the severity of the primary cases in FCs was much higher than that of the secondary cases due to the older age and greater underlying disease of the latter patients.