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Modeling population harvesting of rodents for the control of hantavirus infection

Yusof F, Md. Ismai l, Ali N

Sains Malaysiana, 2010;39.

Hantaviruses are infectious agents that can cause diseases resulting in deaths in humans and are hosted by rodents without affecting the hosts themselves. A simple mathematical model describing the spread of the Hantavirus infection in rodents has been proposed and developed by Abramson and Kenkre where the model takes into account the temporal and spatial characteristics of this infection. In this paper, we extended this model to include the process of harvesting and study the impact of different harvesting strategies in the spread of the Hantavirus infection in rodents. Several numerical simulations were carried out and the results are discussed.

Matched MeSH terms: Hantavirus; Hantavirus Infections
Fulltext Serological evidence of hantavirus infections in Malaysia

Lam SK, Chua KB, Myshrall T, Devi S, Zainal D, Afifi SA, et al.

Southeast Asian J. Trop. Med. Public Health, 2001 Dec;32(4):809-13.
PMID: 12041558

Hantaviruses are primarily rodent-borne and transmission is by inhalation of virus-contaminated aerosols of rodent excreta, especially urine and saliva. The genus Hantavirus, family Bunyaviridae, comprises at least 14 serotypes and the symptoms of clinical illness range from mild fever to severe hemorrhagic manifestations with renal complications. Many countries in Southeast Asia are unaware of the importance of hantavirus infections and give them low priority. Malaysia, like other countries in the region, has conducted very few studies on the epidemiology of hantaviruses - and even these were conducted in the 1980s. Using a more extensive range of hantavirus antigens, we conducted a seroprevalence study of rodents and humans and found further evidence of hantavirus infections. Moreover, the data from the antibody profiles strongly suggest the presence of different hantaviruses at the study sites.

Matched MeSH terms: Hantavirus/immunology; Hantavirus Infections/diagnosis*; Hantavirus Infections/epidemiology
Effect of predators on the spread of hantavirus infection

Yusof F, Md Ismail A.I.B., Ali N

Sains Malaysiana, 2014;43:1045-1051.

Hantavirus is a serious disease caused by rodents which can lead to mortality. Many efforts have been carried out by researchers to develop and analyze mathematical models of Hantavirus infection. In this paper, the Peixoto and Abramson (2006) biodiversity model is modified to include the effect of predators and study the prediction of the modified model. When rodent and predator populations are in competition, the predator populations have the effect of reducing the prevalence of infection. Predators may be used for control and reduces the number of competing species to stabilize the populations at a persistent equilibrium.

Matched MeSH terms: Hantavirus; Hantavirus Infections
Fulltext Implication of predator interaction of the spread of hantavirus infection

Yusof, F. M., Md. Ismail, A. I. B., Abu Hasan, Y.

MATEMATIKA, 2018;34(2):205-226.
MyJurnal

Hantaviruses are etiological agents of zoonotic diseases and certain other dis-
eases, which pose a serious threat to human health. When rodent and predator popula-
tions share in an ecology, the competitive force of the populations can lead to a reduction
or elimination of a hantavirus outbreak. The effect of the predator eliminating rodents
and predator populations that tends to reduce or eliminate hantavirus infection is investi-
gated. The existence of several equilibrium points of the model is identified and local and
global stabilities of the model at these equilibrium points are analysed in detail. Numerical
simulations are carried out to illustrate our model results.

Matched MeSH terms: Hantavirus; Hantavirus Infections
Effects Of Biotic Interactions, Abiotic Environments And Harvesting On The Spread Of Hantavirus Infection

Fauzi Mohamed Yusof, Mohd Hafiz Mohd, Yazariah Mohd Yatim, Ahmad Izani Md. Ismail

MATEMATIKA, 2020;36(1):1-14.
MyJurnal

In this paper, the combined influences of biotic interactions, environmental components and harvesting strategy on the spread of Hantavirus are investigated. By employing a multi-species model consisting of (susceptible and infected) rodents and alien species, we show that interspecific competition from alien species has an effect in reducing the spread of infection, and this species could be employed as a potential biocontrol agent. Our analysis using numerical continuation and simulation also reveals the conditions under which Hantavirus infection occurs and disappears as the environmental conditions and the intensity of harvesting change. Without harvesting, infection emerges when environments are conducive. Inclusion of moderate harvesting in favourable environments can lead to disappearance of infection among rodent species. However, as the intensity of harvesting increases, this situation can cause extinction of all rodents species and consequently, jeopardise biodiversity. Overall, our results demonstrate how the interplay of different factors can combine to determine the spread of infectious diseases.

Matched MeSH terms: Hantavirus; Hantavirus Infections
Haemorrhagic fever with renal syndrome: clinical, virological and epidemiological perspectives

Chan YC, Wong TW, Yap EH

Ann Acad Med Singap, 1987 Oct;16(4):696-701.
PMID: 2895603

Haemorrhagic fever with renal syndrome (HFRS) is caused by a group of RNA viruses within the family of Bunyaviridae known as hantaviruses. The classical, severe form of HFRS is characterized by fever, headache, abdominal and lumbar pain, proteinuria, haemorrhagic phenomena, shock and renal failure. The disease is associated with the prototype Hantaan virus and occurs in rural areas of Korea and China with Apodemus mice as reservoir hosts. A clinically less severe form of HFRS, which is caused by Seoul virus, occurs in urban areas with the house rat Rattus novegicus as the main reservoir host. The disease in nonendemic areas may be atypical and patients with symptoms the hepatitis and minimal renal involvement have been observed in Malaysia. Outbreaks of HFRS in humans involving infected laboratory rat colonies have occurred in several medical centres in various countries. Hantaviruses cause a chronic, asymptomatic infection in rodents which excrete the virus in their lungs, saliva and urine. Man becomes infected mainly by inhalation of infected droplets from healthy rodent carriers. Seroepidemiological studies using mainly the indirect immunoflourescent antibody test of sera from humans and rats showed that hantaviruses have a worldwide distribution.

Matched MeSH terms: Hantavirus/isolation & purification
Fulltext Rodent Species Distribution and Hantavirus Seroprevalence in Residential and Forested areas of Sarawak, Malaysia

Hamdan NE, Ng YL, Lee WB, Tan CS, Khan FA, Chong YL

Trop Life Sci Res, 2017 Jan;28(1):151-159.
PMID: 28228923 MyJurnal DOI: 10.21315/tlsr2017.28.1.11

Rodents belong to the order Rodentia, which consists of three families in Borneo (i.e., Muridae, Sciuridae and Hystricidae). These include rats, mice, squirrels, and porcupines. They are widespread throughout the world and considered pests that harm humans and livestock. Some rodent species are natural reservoirs of hantaviruses (Family: Bunyaviridae) that can cause zoonotic diseases in humans. Although hantavirus seropositive human sera were reported in Peninsular Malaysia in the early 1980s, information on their infection in rodent species in Malaysia is still lacking. The rodent populations in residential and forested areas in Sarawak were sampled. A total of 108 individuals from 15 species of rodents were collected in residential (n = 44) and forested ( n = 64) areas. The species diversity of rodents in forested areas was significantly higher (H = 2.2342) compared to rodents in residential areas (H = 0.64715) (p < 0.001 of Zar-t test based on the Shannon index). Rattus rattus and Sundamys muelleri were present at high frequencies in both localities. An enzyme-linked immunosorbent assay (ELISA) showed that hantavirus-targeting antibodies were absent from 53 tested serum samples. This is the first report of hantavirus seroprevalence surveillance in rodent populations in Sarawak, East Malaysia. The results suggested that hantavirus was not circulating in the studied rodent populations in Sarawak, or it was otherwise at a low prevalence that is below the detection threshold. It is important to remain vigilant because of the zoonotic potential of this virus and its severe disease outcome. Further studies, such as molecular detection of viral genetic materials, are needed to fully assess the risk of hantavirus infection in rodents and humans in this region of Malaysia.

Matched MeSH terms: Hantavirus; Hantavirus Infections
Emerging viral diseases

Nichol ST, Arikawa J, Kawaoka Y

Proc Natl Acad Sci U S A, 2000 Nov 07;97(23):12411-2.
PMID: 11035785
Matched MeSH terms: Hantavirus Infections/epidemiology*; Hantavirus Infections/transmission; Hantavirus Infections/virology
Haemorrhagic fever with renal syndrome involving the liver

Chan YC, Wong TW, Yap EH, Tan HC, Lee HW, Chu YK, et al.

Med J Aust, 1987 Sep 07;147(5):248-9.
PMID: 2890086

A case of haemorrhagic fever with renal syndrome that originated in Malaysia is reported. The patient presented with clinical symptoms which were not typical of the disease as seen in endemic regions. Renal involvement, which is characteristic of haemorrhagic fever with renal syndrome, was mild, and the predominant symptom was a persistently marked elevation of serum transaminase levels that was suggestive of hepatitis. Liver involvement has not been described in the Asian form of haemorrhagic fever with renal syndrome. The patient developed a petechial skin rash and had severe thrombocytopenia. Serological confirmation of the diagnosis of haemorrhagic fever with renal syndrome was obtained by the demonstration of significant antibody rises to hantaviruses in the patient's acute- and convalescent-phase sera.

Matched MeSH terms: Hantavirus/immunology
Appropriateness of deep vein thrombosis (DVT) prophylaxis use among medical inpatients: a DVT risk alert tool (DRAT) study

Diana Yap FS, Ng ZY, Wong CY, Muhamad Saifuzzaman MK, Yang LB

Med J Malaysia, 2019 02;74(1):45-50.
PMID: 30846662

INTRODUCTION: Increasing incidence of Venous Thromboembolism (VTE) has complicated treatment courses for hospitalised patients. Despite recommendation to support deep vein thrombosis (DVT) risk assessment and appropriate use of prophylaxis in medical inpatients, it is either neglected or prescribed unnecessarily by the clinicians. This study aimed to assess and compare the appropriateness of DVT prophylaxis prescribing between usual care versus a pharmacist-driven DVT Risk Alert Tool (DRAT) intervention among hospitalised medical patients.
METHODS: A prospective pre- and post-intervention study was conducted among medical inpatients in a Malaysian secondary care hospital. DVT and bleeding risks were stratified using validated Padua Risk Assessment Model (RAM) and International Medical Prevention Registry on Venous Thromboembolism (IMPROVE) Bleeding Risk Assessment Model. Pharmacist-driven DRAT was developed and implemented post-interventional phase. DVT prophylaxis use was determined and its appropriateness was compared between pre and post study using multivariate logistic regression with IBM SPSS software version 21.0.
RESULTS: Overall, 286 patients (n=142 pre-intervention versus n=144 post-intervention) were conveniently recruited. The prevalence of DVT prophylaxis use was 10.8%. Appropriate thromboprophylaxis prescribing increased from 64.8% to 68.1% post-DRAT implementation. Of note, among high DVT risk patients, DRAT intervention was observed to be a significant predictor of appropriate thromboprophylaxis use (14.3% versus 31.3%; adjusted odds ratio=2.80; 95% CI 1.01 to 7.80; p<0.05).
CONCLUSION: The appropriateness of DVT prophylaxis use was suboptimal but doubled after implementation of DRAT intervention. Thus, an integrated risk stratification checklist is an effective approach for the improvement of rational DVT prophylaxis use.

Matched MeSH terms: Hantavirus