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Intro: Cardamones variant Wēnzhōu virus (CVWV) is a rodent-borne virus and part of Arenaviridae family. It causes occasionally fatal hemorrhagic in human, but is generally neglected among others zoonotic disease. In Cambodia, the presence of CVWV was detected in 2009 in two Rattus species. It shares more than 85% of identity in S and L segments compared to Wenzhou Mammarenavirus from China, and was shown to be pathogenic in human. To assess the molecular epidemiology of CVWV amount rodents, and the seroprevalence in human and rodents populations in Cambodia Methods: The study was conducted using rodent's serum and pool of organs, and human serum samples, collected in Phnom Penh (the Capital city of Cambodia) and two provinces (Preah Sihanouk and Kampong Cham) representing rural setting, in 2020 and 2022. The presence of CVWV RNA was tested on rodent's pool organs using RT-PCR of GPC and L genes of Arenavirus and Sanger sequencing. The detection of anti-CVWV IgG antibody was performed on rodent and human serum samples using in-house ELISA. Findings: Between 2020 and 2022, 750 pools of organs from rodents and 788 human serum samples were collected. In rodents, the overall prevalence of CVWV was 5.2% (39/750) with the highest prevalence observed in Preah Sihanouk site 3.6% (27/750). Only Rattus exulans 15.4% (32/280) and Rattus norvegicus 4.9% (7/144) species were affected by CVWV. Seroprevalence of anti-CVWV IgG was significantly highest in Rattus norvegicus (58.1%, 72/124), followed by Rattus exulans (13.3%, 24/181) (p < 0.001). In human, seroprevalence of anti-CVWV IgG was between 12.7% (100/788) to 20.3% (112/555) among two visits of 788 participants. Twenty-eight participant remained sero-positive within 2 years period. Conclusion: Our findings provide updates on prevalence and genetic characterization diversity of Mammarenavirus in Cambodia. Further investigations are needed to determine the risk behavior and impact of Arenavirus infection at human-rodent interface.

Intro: Rodent-borne hantaviruses are pathogenic in humans and remain a threat for public health. In Asia, data are available mostly from oriental countries, but limited in South-East Asia. In Cambodia, the presence of hantavirus was reported in rodents since 1998. Nevertheless, burden of infection in humans remains unknown. In our study, we aimed to document the presence and diversity of hantaviruses in rodents and to assess hantavirus seroprevalence in people living in urban and rural settings in Cambodia. Methods: This is a retrospective study conducted using pooled organs collected from 750 rodents in urban and rural settings in 2020 (rainy season) and 2022 (dry season). Concurrently, 788 people working or living at the vicinity of rodent trapping locations were requested for blood collection. Hantavirus RNA in rodents was assessed using RT-PCR and confirmed by Sanger sequencing. Human sera were tested for anti-Thailand hantavirus IgG and IgM using in-house ELISA. Findings: In rodents, hantavirus RNA was detected in 25 (3.3%) caught rodents all originated from urban area. Seoul orthohantavirus was the most predominant virus detected in 23 Rattus norvegicus and 1 Rattus rattus. Thottapalayam virus was detected in one Suncus murinus. In humans, the initial seroprevalence of anti-hantavirus IgG was 10.0% (79/788) in 2020. For 70.4% (555/788) of these study participants, a follow-up blood collection was performed in 2022. Out of these, six (1.1%) individuals turned seroconverted, and one even was positive for hantavirus IgM antibodies. Overall, the hantavirus seroprevalence was significantly higher in urban compared to rural area (13.8% vs. 8.9%, p=0.03). Conclusion: Our findings highlighted a new insight of hantavirus circulation at the rodent-human interface in Cambodia. Additional analyses are ongoing to identify potential factors associated with human exposure to hantavirus. Further investigations are also needed to determine the impact of hantavirus infection on human health in Cambodia.

Cell mass and composition change with cell cycle progression. Our previous work characterized buoyant mass dynamics in mitosis (Miettinen et al., 2019), but how dry mass and cell composition change in mitosis has remained unclear. To better understand mitotic cell growth and compositional changes, we develop a single-cell approach for monitoring dry mass and the density of that dry mass every ~75 s with 1.3% and 0.3% measurement precision, respectively. We find that suspension grown mammalian cells lose dry mass and increase dry mass density following mitotic entry. These changes display large, non-genetic cell-to-cell variability, and the changes are reversed at metaphase-anaphase transition, after which dry mass continues accumulating. The change in dry mass density causes buoyant and dry mass to differ specifically in early mitosis, thus reconciling existing literature on mitotic cell growth. Mechanistically, cells in early mitosis increase lysosomal exocytosis, and inhibition of lysosomal exocytosis decreases the dry mass loss and dry mass density increase in mitosis. Overall, our work provides a new approach for monitoring single-cell dry mass and dry mass density, and reveals that mitosis is coupled to extensive exocytosis-mediated secretion of cellular contents.

Purpose: This study aims to evaluate the implementation of a hospital-based integrated bite case management system (IBCM) in Phnom Penh to identify potential improvements and assess the risk of rabies in human victims to help guide animal health interventions and post-exposure treatment. Methods & Materials: The surveillance programme was initiated from human dog-bite patients presented to the Institute Pasteur du Cambodge (IPC) Vaccination Unit in Phnom Penh for post-exposure prophylactic treatment, or through public reports between October 2020 and June 2021. All identified individuals with knowledge of a biting dog were engaged during the investigation. The standardised questionnaires were administered by phone, or in-person where deemed necessary. Each case was assigned with a rabies status; rabid, probable, suspect/inconclusive, and non-case depending on the outcome of an investigation. Univariate logistic regression was performed with all inputs except for inconclusive cases to evaluate the risk factors in case demographics associated with rabid animals. Results: During the study period, 5,035 investigations were conducted. The surveillance system detected 17 rabid cases associated with human dog-bite patients, and 2 cases through other reports. Fifty-seven cases were defined as probable, and 2,745 biting dogs were considered not rabid at the time of the incidents. A definitive conclusion was not drawn in 2,214 cases. The vaccination rate of known biting dogs was 18.6%. Univariate analyses showed that case demographics from the earliest stage of an investigation including animals showing signs of sickness (OR: 135.8, 95%CI: 42.0 – 439.3), animals’ death described as spontaneous (OR: 111.2, 95%CI: 26.3 – 469.9), animals that were killed (OR: 126.3, 95%CI: 42.4 – 545.3), ownerless animals (OR: 33.5, 95%CI: 11.5 – 97.4), patients older than 15 years old (OR: 5.3, 95%CI: 1.5 – 18.9), and multiple bite victims in a case (OR: 6.8, 95%CI: 2.3 – 20.2) were associated with confirmed rabid cases. Conclusion: The study identified barriers to successful sample collection and thorough follow-up with patients which could impact on the system competency. The results of the study indicated that the initial case demographics could be used to assist not only prioritise cases for the IBCM investigation, but also spare PEP prescription for cases of low risk.

Spatial interpolation of precipitation data is of great importance for hydrological modelling. Geostatistical methods (kriging) are widely applied in spatial interpolation from point measurement to continuous surfaces. The first step in kriging computation is the semi-variogram modelling which usually used only one variogram model for all-moment data. The objective of this paper was to develop different algorithms of spatial interpolation for daily rainfall on 1 km2 regular grids in the catchment area and to compare the results of geostatistical and deterministic approaches. This study leaned on 30-yr daily rainfall data of 70 raingages in the hilly landscape of the Ourthe and Ambleve catchments in Belgium (2908 km2). This area lies between 35 and 693 m in elevation and consists of river networks, which are tributaries of the Meuse River. For geostatistical algorithms, seven semi-variogram models (logarithmic, power, exponential, Gaussian, rational quadratic, spherical and penta-spherical) were fitted to daily sample semi-variogram on a daily basis. These seven variogram models were also adopted to avoid negative interpolated rainfall. The elevation, extracted from a digital elevation model, was incorporated into multivariate geostatistics. Seven validation raingages and cross validation were used to compare the interpolation performance of these algorithms applied to different densities of raingages. We found that between the seven variogram models used, the Gaussian model was the most frequently best fit. Using seven variogram models can avoid negative daily rainfall in ordinary kriging. The negative estimates of kriging were observed for convective more than stratiform rain. The performance of the different methods varied slightly according to the density of raingages, particularly between 8 and 70 raingages but it was much different for interpolation using 4 raingages. Spatial interpolation with the geostatistical and Inverse Distance Weighting (IDW) algorithms outperformed considerably the interpolation with the Thiessen polygon, commonly used in various hydrological models. Integrating elevation into Kriging with an External Drift (KED) and Ordinary Cokriging (OCK) did not improve the interpolation accuracy for daily rainfall. Ordinary Kriging (ORK) and IDW were considered to be the best methods, as they provided smallest RMSE value for nearly all cases. Care should be taken in applying UNK and KED when interpolating daily rainfall with very few neighbourhood sample points. These recommendations complement the results reported in the literature. ORK, UNK and KED using only spherical model offered a slightly better result whereas OCK using seven variogram models achieved better result.

Germanium has become a promising material for creating CMOS-compatible optoelectronic devices, such as modulators and detectors employing the Franz-Keldysh effect (FKE) or the quantum-confined Stark effect (QCSE), which meet strict energy and density requirements for future interconnects. To improve Ge-based modulator design, it is important to understand the contributions to the insertion loss (IL). With indirect absorption being the primary component of IL, we have experimentally determined the strength of this loss and compared it with theoretical models. For the first time, we have used the more sensitive photocurrent measurements for determining the effective absorption coefficient in our Ge/SiGe quantum well material employing QCSE. This measurement technique enables measurement of the absorption coefficient over four orders of magnitude. We find good agreement between our thin Ge quantum wells and the bulk material parameters and theoretical models. Similar to bulk Ge, we find that the 27.7 meV LA phonon is dominant in these quantum confined structures and that the electroabsorption profile can be predicted using the model presented by Frova, Phys. Rev., 145 (1966).