Objectives: To investigate the impact of COVID-19 pandemic measures on hospitalizations and the alterations and persistence of the epidemiological patterns of 12 common respiratory pathogens in children during the COVID-19 pandemic and after the cessation of the “zero-COVID-19” policy in southern China. Methods: Respiratory specimens were collected from hospitalized children with acute respiratory infections at Shenzhen Children’s Hospital from January 2020 to June 2024. Twelve common respiratory pathogens were detected using multiplex PCR. Data on demographic characteristics, pathogen detection rates, epidemiological patterns, co-infections, and ICU admission rates were compared between the ‘during COVID-19’ period (Phase 1: January 2020 to December 2022) and the ‘post COVID-19’ period (Phase 2: January 2023 to June 2024). Results: In Phase 2, there was a significant increase in average annual cases, with a higher median age of affected children, higher pathogen detection rates, and increased co-infection rates compared to Phase 1. The epidemiological patterns of most pathogens were altered by the COVID-19 pandemic. Human Parainfluenza Virus, Human Metapneumovirus, Human Bocavirus (HBOV), and Human Coronavirus remained active during Phase 1, while Mycoplasma pneumoniae (Mp) and Adenovirus (ADV) were low, and Respiratory Syncytial Virus (RSV) lacked a seasonal peak in 2022. In Phase 2, Mp, ADV, and RSV experienced outbreaks, with Mp’s high prevalence continuing into 2024. RSV showed out-of-season epidemics for two consecutive years. Influenza A (H1N1), Influenza A (H3N2), and InfB lost their seasonal patterns during Phase 1 but reemerged and regained their seasonal characteristics in 2023–2024. ICU admission rates did not significantly differ between the two phases, except for HBOV, which had higher rates in Phase 2. Conclusion: The epidemiological patterns of various respiratory pathogens were affected by the COVID-19 pandemic to varying degrees. Pathogens suppressed during the pandemic experienced outbreaks or out-of-season epidemics after the lifting of non-pharmaceutical interventions, with Mp and RSV continuing into the second year and HBOV associated ICU admission rates increasing in the post-pandemic era. Continuous monitoring of these patterns is essential to understand the duration of these effects and to inform effective response strategies.

Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening immune-mediated disease that affects patients with known genetic defects and is increasingly found among those with autoimmune diseases and persistent infections. Talaromyces marneffei (TM) is a human opportunistic fungus that commonly infects immunodeficient or immunosuppressed individuals. Few TM-associated secondary HLH cases resulting from autoimmune deficiency have been reported previously. The current case study describes a pediatric patient hospitalized with recurrent fever and lymphadenopathy. The child had abnormal blood cell classification, and microscopy revealed mature granulocytes that phagocytized fungal spores. It was speculated that the patient was infected with TM. The pathogen was detected earlier than the blood culture and confirmed by metagenomic next-generation sequencing. Whole-exome sequencing revealed that the patient had complex mutations associated with immunodeficiency. This included a mutation in exon 3 of the CD40LG gene, c.346G>A, which may be linked to hyper-IgM syndrome, a primary immunodeficiency disease with immunoglobulin conversion recombination defects that could explain the patient’s increased susceptibility to serious opportunistic infections. In addition, a heterozygous frameshift variant, c.820dup (p.Asp274GlyfsTer61), was detected in exon 6 of CARD9, a key gene associated with fungal immune surveillance. After 4 days of fungal treatment, the abnormal blood cell clusters disappeared, but other infections occurred in succession for 6 months after rehabilitation. The patient was followed with the aim of providing subsequent immunotherapy. This study found that infection can trigger HLH in HIV-negative individuals, highlighting the importance of early definitive identification of the causative agent and investigation of potential immunodeficiency.

Background: Myiasis is caused by dipterous larvae, and rarely affects the mouth. Diagnosis by traditional means is easy to be confused with other similar species. Here, we report a case of oral myiasis, in a 5-month-old infant who was diagnosed by morphological examination and molecular biological methods. Case presentation: A 5-month old infant with acute myeloid leukemia was admitted due to recurrent skin masses for more than 4 months. The infant had lip swelling, which prevented him from closing the mouth and membranes were present in his mouth and there were also oral ulcers and erosions. Ten maggots were found in the mouth and one in the ear canal with pus flowing out and were confirmed as the third stage larvae of Sarcophaga ruficornis by morphological examination and a comparison of sequence of cytochrome oxidase subunit 1 (COX1) gene. After removal of the maggots and chemotherapy, the infant ’s condition was gradually improved. Conclusions: To the best of our our knowledge, this is the first neonatal oral myiasis case reported in China and its diagnosis requires a high index of suspicion. Microscopy combined with specific DNA sequence analysis is an effective technological tool to provide rapid diagnoses of the larva specimen and cases of rare diseases, as illustrated in the current case.