Crimean-Congo Hemorrhagic Fever Virus Diversity and Reassortment, Pakistan, 2017-2020.

Sporadic cases and outbreaks of Crimean-Congo hemorrhagic fever (CCHF) have been documented across Pakistan since 1976; however, data regarding the diversity of CCHF virus (CCHFV) in Pakistan is sparse. We whole-genome sequenced 36 CCHFV samples collected from persons infected in Pakistan during 2017-2020. Most CCHF cases were from Rawalpindi (n = 10), followed by Peshawar (n = 7) and Islamabad (n = 4). Phylogenetic analysis revealed the Asia-1 genotype was dominant, but 4 reassorted strains were identified. Strains with reassorted medium gene segments clustered with Asia-2 (n = 2) and Africa-2 (n = 1) genotypes; small segment reassortments clustered with the Asia-2 genotype (n = 2). Reassorted viruses showed close identity with isolates from India, Iran, and Tajikistan, suggesting potential crossborder movement of CCHFV. Improved and continuous human, tick, and animal surveillance is needed to define the diversity of circulating CCHFV strains in Pakistan and prevent transmission.

Serotype and genomic diversity of dengue virus during the 2023 outbreak in Pakistan reveals the circulation of genotype III of DENV-1 and cosmopolitan genotype of DENV-2.

Dengue, a mosquito-borne viral disease, poses a significant public health challenge in Pakistan, with a significant outbreak in 2023, prompting our investigation into the serotype and genomic diversity of the dengue virus (DENV). NS-1 positive blood samples from 153 patients were referred to the National Institute of Health, Pakistan, between July and October 2023. Among these, 98 (64.1%) tested positive using multiplex real-time PCR, with higher prevalence among males (65.8%) and individuals aged 31-40. Serotyping revealed DENV-1 as the predominant serotype (84.7%), followed by DENV-2 (15.3%). Whole-genome sequencing of 18 samples (DENV-1 = 17, DENV-2 = 01) showed that DENV-1 (genotype III) samples were closely related (>99%) to Pakistan outbreak samples (2022), and approx. > 98% with USA (2022), Singapore and China (2016), Bangladesh (2017), and Pakistan (2019). The DENV-2 sequence (cosmopolitan genotype; clade IVA) shared genetic similarity with Pakistan outbreak sequences (2022), approx. > 99% with China and Singapore (2018-2019) and showed divergence from Pakistan sequences (2008-2013). No coinfection with dengue serotypes or other viruses were observed. Comparisons with previous DENV-1 sequences highlighted genetic variations affecting viral replication efficiency (NS2B:K55R) and infectivity (E:M272T). These findings contribute to dengue epidemiology understanding and underscore the importance of ongoing genomic surveillance for future outbreak responses in Pakistan.

Molecular characterization of rotavirus indicates predominance of G9P[4] genotype among children with acute gastroenteritis: First report after vaccine introduction in Pakistan.

Globally, Group A rotavirus (RVA) is the leading cause of acute gastroenteritis in children under 5 years old, with Pakistan having the highest rates of RVA-related morbidity and mortality. The current study aims to determine the genetic diversity of rotavirus and evaluate the impact of Rotarix-vaccine introduction on disease epidemiology in Pakistan. A total of 4749 children, hospitalized with acute gastroenteritis between 2018 and 2020, were tested at four hospitals in Lahore and Karachi. Of the total, 19.3% (918/4749) cases were tested positive for RVA antigen, with the positivity rate varying annually (2018 = 22.7%, 2019 = 14.4%, 2020 = 20.9%). Among RVA-positive children, 66.3% were under 1 year of age. Genotyping of 662 enzyme-linked immuno sorbent assay-positive samples revealed the predominant genotype as G9P[4] (21.4%), followed by G1P[8] (18.9%), G3P[8] (11.4%), G12P[6] (8.7%), G2P[4] (5.7%), G2P[6] (4.8%), and 10.8% had mixed genotypes. Among vaccinated children, genotypes G9P[4] and G12P[6] were more frequently detected, whereas a decline in G2P[4] was observed. Phylogenetic analysis confirmed the continued circulation of indigenous genotypes detected earlier in the country except G9 and P[6] strains. Our findings highlight the predominance of G9P[4] genotype after the vaccine introduction thus emphasizing continual surveillance to monitor the disease burden, viral diversity, and their impact on control of rotavirus gastroenteritis in children.

Genomic characterization of human respiratory syncytial virus circulating in Islamabad, Pakistan, during an outbreak in 2022-2023.

In this study, conducted at the National Institute of Health, Islamabad, during an outbreak of human respiratory syncytial virus (hRSV) from December 2022 to January 2023, the first whole-genome sequences of hRSV isolates from Islamabad, Pakistan, were determined. Out of 10 positive samples, five were sequenced, revealing the presence of two genotypes: RSV-A (GA2.3.5, ON1 strain) and RSV-B (GB5.0.5.a, BA-10 strain). A rare non-synonymous substitution (E232G) in G the protein and N276S in the F protein were found in RSV-A. In RSV-B, the unique mutations K191R, Q209R, and I206M were found in the F protein. These mutations could potentially influence vaccine efficacy and viral pathogenicity. This research underscores the importance of genomic surveillance for understanding RSV diversity and guiding public health responses in Pakistan.

Integrated approach for detection of SARS-CoV-2 and its variant by utilizing LAMP and ARMS-PCR.

Global impact of COVID-19 pandemic has heightened the urgency for efficient virus detection and identification of variants such as the Q57H mutation. Early and efficient detection of SARS-CoV-2 among densely populated developing countries is paramount objective. Although RT-PCR assays offer accuracy, however, dependence on expansive kits and availability of allied health resources pose an immense challenge for developing countries. In the current study, RT-LAMP based detection of SARS-Cov-2 with subsequent confirmation of Q57H variant through ARMS-PCR was performed. Among the 212 collected samples, 134 yielded positive results, while 78 tested negative using RT-LAMP. Oropharyngeal swabs of suspected individuals were collected and processed for viral RNA isolation. Isolated viral RNA was processed further by using either commercially available WarmStart Master Mix or our in house developed LAMP master mix separately. Subsequently, the end results of each specimen were evaluated by colorimetry. For LAMP assays, primers targeting three genes (ORF1ab, N and S) were designed using PrimerExplorer software. Interestingly, pooling of these three genes in single reaction tube increased sensitivity (95.5%) and specificity (93.5%) of LAMP assay. SARS-CoV-2 positive specimens were screened further for Q57H mutation using ARMS-PCR. Based on amplicon size variation, later confirmed by sequencing, our data showed 18.5% samples positive for Q57H mutation. Hence, these findings strongly advocate use of RT-LAMP-based assay for SARS-CoV-2 screening within suspected general population. Furthermore, ARMS-PCR also provides an efficient mean to detect prevalent mutations against SARS-Cov-2.

First report of coinfection and whole-genome sequencing of norovirus and sapovirus in an acute gastroenteritis patient from Pakistan.

Acute gastroenteritis is one of the most common diseases in infants and children in developing countries including Pakistan. In Pakistan, rotavirus (RVA) is known to contribute significantly to pediatric diarrheal illness, but the contribution of other viruses is still unclear. In the current study we have identified a case of mixed infection of norovirus (NoV) and sapovirus (SaV) in a 2-year-old child with acute gastroenteritis. The sample was initially processed for the detection of group A RVA through ELISA followed by NoV using RT-PCR assay. The sample tested positive for NoV RNA and was later subjected to whole-genome sequencing using meta-genome approach on Miseq (Illumina) platform. Sequencing results revealed GII.15 genotype of NoV that clustered with viruses from China and USA from 2017 to 2021. We also retrieved the complete genome of SaV (GI.1 genotype) from the same sample and phylogenetic analysis showed clustering with strains reported from Japan, South Korea, US, and Taiwan during 2012-2016. This is the first report from Pakistan that confirms coinfection of NoV and SaV and elucidates their whole genomes. We recommend initiation of NoV and SaV surveillance program to ascertain disease burden and explore genetic diversity, especially as RVA vaccines have been included in national immunization program.

Whole-genome sequencing of Crimean-Congo hemorrhagic fever virus circulating in Pakistan during 2022.

Pakistan is an endemic country for Crimean-Congo hemorrhagic fever (CCHF) and its Balochistan province is considered a hotspot region for circulation of the virus whereas sporadic cases have been reported from other parts of the country. Our study aims to investigate the genomic diversity of the CCHF virus circulating in Punjab and Khyber Pakhtunkhwa provinces of Pakistan. Between April to September 2022, 46 samples from suspected CCHF patients were tested, with 6 (13%) showing positive RT-PCR results. Among the positive cases, all were male, aged 14-48 years among which 4 were butchers. Three CCHF patients succumbed to the disease. The complete S-M-L-gene fragments of 4 positive samples were sequenced. The S and L segments belonged to the Asia-1 clade and clustered with regional strains from Iran, India, and Afghanistan. One M segment sequence grouped into Africa-2 along with those reported from India during 2016-2019. We report the detection of a reassorted virus (NIH-PAK-CCHF-03|2022) having Asia-1-Africa-2-Asia-1 (S-M-L) segment pattern for the first time from Pakistan. Mutational analysis showed M segments harboring eight mutations (T55A, S80P, T110I, T185A, T189A, A212T, and N239I/T) in the mucin-like domain, five mutations (D250N, T333S, I375V, M401I, A433T), four mutations (N545D, Y657F, K688R, and I824V) in GP38-domain, and three mutations (T1418N, A1431V, and G1449S) in Gc-domain. These findings highlight the significance of whole-genome sequencing of indigenous strains for a better understanding of the CCHFV evolution in Pakistan.

Genomic characterization of the first mpox and varicella-zoster co-infection in Pakistan (2023) through next-generation sequencing.

The global mpox outbreak spanning 2022-2023 has affected numerous countries worldwide. In this study, we present the first report on the detection, whole-genome sequence, and coinfection of the mpox virus and varicella zoster virus (VZV) from Pakistan. During April-May 2023, samples from 20 suspected cases of mpox were tested at the National Institutes of Health, Islamabad among which 4 tested positive. All four cases had a travel history of Saudi Arabia. All the suspected samples were processed by using a Zymo research kit for DNA extraction, followed by qRT-PCR amplification by using a DaAn Gene detection kit for the mpox virus. Further, two of the positive samples with a low Ct value (<20) were subjected to whole-genome sequencing using a metagenomic approach on the iSeq (Illumina) platform. The sequencing results revealed Clade IIb and genotype A.2.1 of MPXV, which clustered with viruses from Slovenia and the UK in July and June 2022, respectively. Our analysis identified two novel nonsynonymous substitutions in mpox virus, namely V98I in OPG046 and P600S in OPG109. Furthermore, we successfully retrieved the complete genome of VZV from the same sample, belonging to Clade 5. This study represents the first positive case of MPXV in Pakistan and the coinfection of mpox and VZV by using a metagenome approach providing insights into their complete genomes. Our results highlight the importance of surveillance at the point of entries, strengthening lab capacities including next-generation sequencing, and using differential diagnosis for timely and accurate detection of mpox cases.

Genomic diversity of SARS-CoV-2 in Pakistan during the fourth wave of pandemic.

The emergence of different variants of concern of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has resulted in upsurges of coronavirus disease 2019 (COVID-19) cases around the globe. Pakistan faced the fourth wave of COVID-19 from July to August 2021 with 314,786 cases. To understand the genomic diversity of circulating SARS-CoV-2 strains during the fourth wave of the pandemic in Pakistan, this study was conducted. The samples from 140 COVID-19-positive patients were subjected to whole-genome sequencing using the iSeq Sequencer by Illumina. The results showed that 97% (n = 136) of isolates belonged to the delta variant while three isolates belonged to alpha and only one isolate belonged to the beta variant. Among delta variant cases, 20.5% (n = 28) isolates were showing B.1.617.2 while 23.5% (n = 25), 17.59% (n = 19), 14.81% (n = 16), and 13.89% (n = 15) of isolates were showing AY.108, AY.43 AY.127, and AY.125 lineages, respectively. Islamabad was found to be the most affected city with 65% (n = 89) of delta variant cases, followed by Karachi (17%, n = 23), and Rawalpindi (10%, n = 14). Apart from the characteristic spike mutations (T19R, L452R, T478K, P681R, and D950N) of the delta variant, the sublineages exhibited other spike mutations as E156del, G142D, T95I, A222V, G446V, K529N, N532S, Q613H, and V483A. The phylogenetic analysis revealed the introductions from Singapore, the United Kingdom, and Germany. This study highlights the circulation of delta variants (B.1.617.2 and sublineages) during the fourth wave of pandemic in Pakistan.

Genomic surveillance reveals the detection of SARS-CoV-2 delta, beta, and gamma VOCs during the third wave in Pakistan.

SARS-CoV-2 variants of concern (VOCs) have emerged worldwide and gained significant importance due to their high transmissibility and global spread, thus meriting close monitoring. In Pakistan, limited information is available on circulation of these variants as the alpha variant has been reported the main circulating lineage. The current study was designed to detect and explore the genomic diversity of SARS-CoV-2 lineages circulating during the third wave of the pandemic in the indigenous population. From May 01 to June 09, 2021, a total of 16 689 samples were tested using TaqPath™ COVID-19 kit for the presence of SARS-CoV-2. Overall, 2562 samples (15.4%) were COVID-19 positive. Out of these positive samples, 2124 (12.7%) did not show the spike gene amplification (spike gene target failure ([SGTF]), whereas 438 (2.6%) showed spike gene amplification (non-SGTF). A subset (n = 58/438) of non-SGTF samples were randomly selected for whole-genome sequencing. Among VOCs, 45% (n = 26/58) were delta, 46% (n = 27/58) were beta, and one was gamma variant. The delta variant cases were reported mainly from Islamabad (n = 15; 58%) followed by Rawalpindi and Azad Kashmir (n = 1; 4% each). Beta variant cases originated mainly from Karachi (n = 8; 30%) and Islamabad (n = 11; 41%) and the gamma variant case was reported in a traveler from Italy. The delta, beta, and gamma variants possessed lineage-specific spike mutations. Notably, two rare mutations (E484Q and L5F) were found in the delta variant. Furthermore, in the beta variant, two significant rare non-synonymous spike mutations (A879S and K444R) were also reported. High prevalence of beta and delta variants in local population may increase the number of cases in the near future and provides an early warning to national health authorities to take timely decisions and devise suitable interventions to contain a possible fourth wave.

Molecular identification and characterization of measles virus genotypes circulating in Afghanistan, 2008-2018.

The measles virus (MV) remains a leading cause of morbidity and mortality in children under 5 years of age. Molecular identification of circulating wild-type MV) strains is a vital component of the measles elimination program. We received 159 oral swab samples from Afghanistan during 2008-2018. Viral RNA was extracted, followed by one-step RT-PCR and positive amplicons were subject to sequencing for genotype identification. Out of 159 total samples, 52% (83/159) were detected positive by RT-PCR. Genotype D4 was identified from 2.4% (2/83), genotype H1, 4.8% (4/83), and genotype B3, 92.7% (77/83) cases, respectively.

Epidemiology of Chikungunya virus isolates 2016-2018 in Pakistan.

The chikungunya virus (CHIKV) is a mosquito-transmitted alphavirus, which has infected millions of people in Africa, Asia, Americas, and Europe since it remerged in India and Indian Ocean regions in 2005-2006. The purpose of this study was to evaluate the genetic diversity and evolutionary changes in CHIKV from 2016 to 2018 in Pakistan. Blood specimens were collected and processed following the Centers for Disease Control and Prevention Trioplex Protocol. Sequencing and phylogenetic analysis of complete coding sequence of representative isolates from the CHIKV outbreak was carried out during December 2016 to July 2018, a total of 1549 samples were received, out of which 50% (n = 774) were found positive for CHIKV RNA. Mean age of chikungunya positive patients was 31.8 ± 15.7 years and most affected were between 21 and 40 years of age. The Pakistan CHIKV strains clustered with the Indian Ocean sublineage of East/Central/South African with cocirculation of some variants In the structural proteins region, two noteworthy changes (A226V and D284E) were observed in the membrane fusion glycoprotein E1. Key substitutions in the neutralizing epitopes site and a few changes indicative of adaptive to other insect cells were also detected in Pakistani strains. This study provides the emerging trend of CHIKV in the country for early identification of potential variants of high virulence and preventive measures for vector borne disease especially in the endemic areas.

Genetic Epidemiology Reveals 3 Chronic Reservoir Areas With Recurrent Population Mobility Challenging Poliovirus Eradication in Pakistan.

BACKGROUND: Pakistan is among 3 countries endemic for wild poliovirus type 1 (WPV1) circulation that are still struggling for eradication of poliomyelitis. Active clinical and environmental surveillance with meticulous laboratory investigations provide insights into poliovirus transmission patterns and genomic diversity to inform decisions for strategic operations required to achieve eradication. METHODS: We analyzed epidemiological and virological data to comprehend the current epidemiological status of WPV1 in Pakistan during 2015-2017. Stool specimens of patients with acute flaccid paralysis (AFP) and sewage samples collected from 60 environmental sites were tested. Viral culturing, intratypic differentiation by real-time polymerase chain reaction, and nucleic acid sequencing of the VP1 region of the poliovirus genome to determine genetic relatedness among WPV1 strains were applied. RESULTS: Poliovirus isolates were grouped into 11 distinct clusters, which had ≥95% nucleotide homology in the VP1 coding region. Most of the poliovirus burden was shared by 3 major reservoirs: Karachi, Peshawar, and Quetta block (64.2% in 2015, 75.4% in 2016, and 76.7% in 2017). CONCLUSIONS: Environmental surveillance reveals importations and pockets of unimmunized children that dictate intensive target mop-up campaigns to contain poliovirus transmission. A decrease in the number of orphan isolates reflects effective combination of AFP and environmental surveillance in Pakistan. The genetic data reflect sustained transmission within reservoir areas, further expanded by periodic importations to areas of high immunity reflected by immediate termination of imported viruses. Improved immunization coverage with high-quality surveillance is vital for global certification of polio eradication.

Rotavirus surveillance in Pakistan during 2015-2016 reveals high prevalence of G12P[6].

The G12 rotavirus genotype has emerged globally since their first detection in 1987 from the Philippines; however it remains a rare cause of gastroenteritis in Pakistan. Rotavirus surveillance conducted during 2015-2016, assessed 3446 children <5 years hospitalized for gastroenteritis and found 802 (23.2%) positive on ELISA. Genotyping of a subset of positive samples (n = 319) revealed G12P[6] (11.28%) as the third most common G/P combination following G3P[8] (28.5%) and G1P[8] (12.5%); G2P[4] (10.65%) and G3P[6] (8.15%) were other frequently detected strains. Phylogenetic analysis of G12 strains from Pakistan revealed high genetic similarity to G12 strains from Italy, Thailand, Korea, and Great Britain as well as local strains within G12 lineage III. In conclusion, G12P[6] was a major contributor of RVA gastroenteritis in Pakistani children. Robust surveillance after the introduction of rotavirus vaccines will help determine the evolution of G12 and other circulating genotypes in the country.

Epidemiological and molecular investigation of a measles outbreak in Punjab, Pakistan, 2013-2015.

Despite the availability of an effective vaccine, the measles virus continues to cause significant morbidity and mortality in children worldwide. Molecular characterization of wild-type measles strains is an invaluable component of epidemiological studies or surveillance systems that provides important information pertinent to outbreak linkages and transmission pathways. Serum samples and throat swabs were collected from suspected measles cases from the Punjab province of Pakistan (2013-2015) and further tested for measles immunoglobulin M (IgM) through enzyme-linked immunosorbent assay and reverse-transcriptase polymerase chain reaction for molecular characterization. Among the total of 5415 blood samples, 59% tested positive for measles IgM. Males had a higher infection rate (55%) than females (45%), and the highest frequency of positive cases (63%) was found in the age group of 0 to 5 years. Partial sequencing of the nucleoprotein gene showed that 27 strains belonged to the B3 genotype, whereas 2 viruses were identified as D4. On phylogenetic analysis, Pakistani B3 strains were found to be closely related to previously reported indigenous strains and those from neighboring countries of Iran and Qatar. This is the first report on the detection of the measles B3 genotype from Punjab, Pakistan. The current study shows a high burden of measles infections in Punjab province owing to poor routine immunization coverage in major cities. It is imperative that national health authorities adopt strategic steps on an urgent basis for improvement of routine immunization coverage. Molecular epidemiology of the measles viruses circulating in different parts of the country can provide useful data to manage future outbreaks.

A measles outbreak in Sindh, Pakistan caused by a genotype B3 virus.

Measles continues to be a major public health issue causing substantial outbreaks worldwide, mostly affecting young children. Molecular analysis of measles viruses provides important information on outbreak linkages and transmission pathways that can be helpful towards implementation of appropriate control programs. In Pakistan, the control of measles is still tenuous, and progress towards elimination has been irregular and challenging. In the 2013 measles outbreak we received 4,682 sera collected from suspected patients in 23 districts across Sindh. A total of 3,283 samples were confirmed measles positive using IgM ELISA with the highest infection rate in children aged 1-12 months. Males were more affected than females and a visible peak was observed from January to April. Among the 3,283 cases, 59.1% were unvaccinated, 29.6% had received 1 dose and 10.3% had received 2 doses of measles vaccine while 0.85% had an unknown vaccination status. For genotype detection and phylogenetic analysis, 60 throat swab samples were collected from suspected patients below 15 years of age in eight districts of Sindh province. Forty four (73%; 44/60) throat swab samples were successfully genotyped using RT-PCR. Phylogenetic analyses based on partial sequences of the nucleocapsid protein gene revealed that all Pakistani measles virus strains belonged to genotype B3 and were closely related to those isolated from neighboring countries such as Iran, Afghanistan (99.1-100%) and India with 98.6 - 99.6% nucleotide homology. This is the first report on the phylogenetic analysis of measles B3 genotype strains from Pakistan and highlights the need for strengthening the surveillance systems and improving immunization coverage across the country.

Evolutionary analysis of seasonal influenza A viruses in Pakistan 2020-2023.

INTRODUCTION: Influenza A viruses cause global health concerns due to their high amino acid substitution rates. They are linked to yearly seasonal epidemics and occasional pandemics. This study focused on sequencing influenza A virus strains in Pakistan. MATERIALS AND METHODS: We analyzed the genetic characteristics of influenza A(H1N1)pdm09 and A(H3N2) viruses circulating in Pakistan from January 2020 to January 2023. Whole genome sequences from influenza A (n = 126) virus isolates were amplified and sequenced by the Oxford Nanopore (MinION) platform. RESULTS: The HA genes of influenza A(H1N1)pdm09 underwent amino acid substitutions at positions K54Q, A186T, Q189E, E224A, R259K, and K308R in sequenced samples. The HA genes of influenza A(H3N2) had amino acid substitutions at G53D, E83K, D104G, I140M, S205F, A212T, and K276R in the sequenced samples. Furthermore, the HA gene sequences of influenza A(H1N1)pdm09 in this study belonged to subclade 6B.1A.5a.2a. Similarly, the HA gene sequences of influenza A(H3N2) were classified under six subclades (3C.3a.1 and 3C.2a1b.2a [2, 2a.1, 2b, 2c, and 2a.3b]). Notably, amino acid substitutions in other gene segments of influenza A(H1N1)pdm09 and A(H3N2) were also found. CONCLUSION: These findings indicate influenza A(H1N1)pdm09 and A(H3N2) viruses co-circulated during the 2020-2023 influenza season in Pakistan. Continued surveillance is crucial for real-time monitoring of possible high-virulence variation and their relevance to existing vaccine strains.