Ocular Manifestations of Flavivirus Infections

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This study is a review on ocular manifestations of flavivirus. This study is expected to have value as an opportunity for medical personnel to consider the possibility of symptoms caused by flavivirus. This study is considered to be a review worthy of publication, especially in that it includes images for diagnosis of each virus infections. However, in order to have medical personnel consider ocular manifestations caused by flavivirus, in addition to the significance of diagnostic methods, the great significance of this paper is to educate the community through the latest preventive methods and inform them of treatment methods. In this regard, the following explanations should be added.

1 When explaining diagnosis by RT-PCR, the relationship with disease stage and the detection sensitivity should be shown. The referenced papers describe the detection period for each RT-PCR detection target, so this should be mentioned in the main text.

2 Regarding preventive methods, the author should collect the latest knowledge about vaccines and state in the paper the type of vaccine that currently offers the most hope (mRNA vaccines, inactivated vaccines, etc.) from evaluating the literature.

3 Medical professionals reading this review are likely to determine whether flaviviruses are the cause of ocular manifestations and then seek information on treatments. Possible applications should also be provided as information. For example, for Dengue virus, the use of Carica papaya leaves has been reported in several papers.

Author Response

We warmly and sincerely thank the reviewers for their thorough reading and comment, which will add a great value to our manuscript. Please find below a complete and point-by-point response to reviewers, with corresponding changes throughout our revised manuscript. The references were also added in the manuscript.

This study is a review on ocular manifestations of flavivirus. This study is expected to have value as an opportunity for medical personnel to consider the possibility of symptoms caused by flavivirus. This study is considered to be a review worthy of publication, especially in that it includes images for diagnosis of each virus infections. However, in order to have medical personnel consider ocular manifestations caused by flavivirus, in addition to the significance of diagnostic methods, the great significance of this paper is to educate the community through the latest preventive methods and inform them of treatment methods. In this regard, the following explanations should be added.

1 When explaining diagnosis by RT-PCR, the relationship with disease stage and the detection sensitivity should be shown. The referenced papers describe the detection period for each RT-PCR detection target, so this should be mentioned in the main text.

We acknowledge reviewer 1's valuable suggestion and have incorporated it in the manuscript for each virus.

Regarding:

· Dengue virus: Lines 193-199“Reported sensitivities of RT-PCR vary widely in medical literature, ranging from 48.4% to 98.2%, depending on sample timing [51]. Sensitivity is higher during the acute phase, coinciding with viremia. Additionally, sensitivity tends to be higher in primary infections compared to secondary infections, indicating the influence of the immune response [52]. RNA detection in urine samples extends beyond the viremic period, up to 16 days, with an estimated sensitivity ranging between 50% and 80% [53]. ”

· West Nile virus: Lines 295-297 “During the viremic period, RT-PCR sensitivity was evaluated at 86.8% in whole-blood samples [80]. Detection rates were lower in serum, cerebrospinal fluid, plasma, and urine, respectively at 26%, 16.6%, 20%, and 58.3%.”

· Yellow fever virus: Lines 357-361 “ Data regarding PCR sensitivities are scarce. A Brazilian study conducted after the last outbreak from 2016 to 2018 indicated detection rates of 8.9% in serum and 50% in blood samples during the viremic phase [98]. Urine sample sensitivity was evaluated at 25% [99]. RNA recovery in urine samples could extend up to 69 days after symptom onset [99].”

· Zika virus: Lines 443-446 “ The rate of RNA detection in serum samples is low, ranging from 41% to 56% within 5 days of symptom onset [134–136], while in urine samples, it is higher at around 95% [136]. Serial serum sampling between days 3 and 13 can detect an additional 25% of cases [134].

· Japanese encephalitis virus: We did not add modifications, as the text already mentioned detection sensitivity of RT-PCR, lines 504-506. “The sensitivity of molecular diagnosis is low, at less than 25% in the acute

phase [156,157]. Combining the two techniques can increase sensitivity to 31% [158].”

· Kyasanur forest fisease virus: Lines 556-558 “ Studies assessing the diagnostic performance of RT-PCR are limited. However, one study demonstrated a low detection rate of approximately 34.3% in serum samples [169].”

2 Regarding preventive methods, the author should collect the latest knowledge about vaccines and state in the paper the type of vaccine that currently offers the most hope (mRNA vaccines, inactivated vaccines, etc.) from evaluating the literature.

We thank reviewer 1 for this suggestion, and we added modifications accordingly.

Regarding:

· Dengue virus: Lines 211-222 “Two live-attenuated tetravalent vaccine are currently available. Dengvaxia® (Sanofi Pasteur, Chimeric viruses YFV/DEN1-4) is administered in three doses spaced six months apart. Its use is reserved for populations in which the seroprevalence is over 70% in the age bracket for vaccination, due to the weak efficacy of the vaccine and the potential long-term risks of severe DF in vaccinated seronegative subjects. The efficacy rate over the initial 25 months was assessed at 60.3% [58]. Vaccination is not recommended for children under 9 years of age [59]. More recently, Qdenga® (Takeda, chimeric viruses DEN-2 PDK-53, DEN-1,-3,-4), administered in two doses with a 3-month interval, has received marketing authorization. The efficacy after two doses in children aged 4 to 16 years was assessed at 80.2% within 12 months [60]. At 18 months, the efficacy was lower, 76.1% in immune recipients, and 66.2% in non-immune recipients [61]. Vaccination could be performed in persons aged above 4 years, regardless of past dengue virus infection.”

· West Nile virus: Lines 306-311 “Four veterinary vaccines are approved for use in horses, requiring annual boosters [85]. Currently, there are no licensed human vaccines available. Only phase 2 clinical trials have been conducted [86]. A live attenuated chimeric vaccine (ChimeriVax WN02) elicited immunogenicity, after a single dose. A predictive model indicated that effective WNV vaccination in areas with increased incidence could potentially reduce the annual morbidity of neuroinvasive diseases cases by 30% and deaths by 60% in United States [87].”

· Yellow fever virus:

o Lines 364-366 “The historical 17 D strain is still used to produce the vaccine. A meta-analysis confirmed a high seroprotection rate after single dose five to ten years after the vaccination [100] .”

o Lines 372-373 “Other YF vaccines candidates are currently in development and have not yet been tested beyond phase 1 clinical trials [103].”

· Zika virus: Lines 455-460 “ A completed phase 2/2B trial assessed a ZIKA DNA vaccine (VRC 5283) expressing prM-E structural genes. This vaccine was immunogenic in humans and generated cross-reactivity but did not produce cross-neutralizing antibodies against other flaviviruses, especially DENV [142]. Another ongoing phase 2 trial evaluates a ZIKA mRNA vaccine (mRNA-1853) delivering modified prM-E mRNA [143]. However, the lack of current outbreaks hinders the advancement of clinical trials.”

· Japanese encephalitis virus: Lines 513-520 “ Currently available vaccines include cell culture-derived live-attenuated, cell culture-derived killed-inactivated and cell culture-derived live-attenuated chimeric [160]. The use of mouse-brain-derived killed-inactivated vaccines, which induced immune adverse events, has been discontinued [160]. Most vaccines are based on the SA14-14-2 strain, providing nearly complete protection with two doses for up to five years [151]. ”

· Kyasanur forest disease virus: Lines 562-566 “ The vaccine's efficacy is estimated at 83% after two doses. Annually administration of booster doses are recommended for five years after the last report of KFD cases in the area [172]. Currently, efforts are ongoing to optimize this vaccine by reducing formalin concentration to mitigate side effects such as swelling and irritation, aiming to enhance vaccine acceptance [173]. ”

3 Medical professionals reading this review are likely to determine whether flaviviruses are the cause of ocular manifestations and then seek information on treatments. Possible applications should also be provided as information. For example, for Dengue virus, the use of Carica papaya leaves has been reported in several papers.

We thank reviewer 1 for this suggestion, and we added modifications accordingly.

Regarding:

· Dengue virus: Lines 205-208 “ Various herbal remedies, such as Carica papaya, have been employed in treating DF. [56]. A meta-analysis on Carica papaya indicated potential benefits in improving platelet count during DF and reducing hospital stays, although evidence quality was low [57].”

· West Nile virus: The sentence lines 299-301 was already present: “Ongoing clinical trials are exploring novel therapeutic strategies, including interferon alpha-2b, interferon beta, and high-titer intravenous immunoglobulin [81-83]. ” We added, line 301: “Potential in-vitro antiviral compounds include Delphinidin and Epigallocatechin Gallate [84]. ”

· Yellow fever virus: Lines 375-380 “ Ongoing clinical trials are investigating novel therapeutic strategies, including phase I human immunoglobulin anti-YFV [106]. A Brazilian randomized clinical trial is assessing the efficacy of the antiviral sofosbuvir, a nucleotide analogue inhibitor, that exhibited activity in-vitro and in animal models [107]. Ribavirin has shown potential activity in vitro but requires high concentrations that are not achievable in human serum [108].”

· Zika virus: Lines 451-453 “No specific treatment is cu

rrently available. However, natural products isolated from medicinal herbs have demonstrated inhibition of ZIKV in vitro [139]. Only one in-vivo animal model is available, reporting the anti-ZIKV activity of emetine [140].”

· Japanase encephalitis virus: Lines 509-512 “Potential in-vitro antiviral compounds include Baicalein, Curcumin and Kaempferol [84]. Specific therapies are inadequate, with corticosteroids, ribavirin, minocycline, intravenous immunoglobulin, and interferon alpha-2a showing inefficacy [151].”

· Kyasanur forest disease virus: Line 560-561 “ Specific therapies are deficient, notably with inefficacy observed with interferon alpha-2a [170].”

Reviewer 2 Report

Comments and Suggestions for Authors

The authors present a review of ophthalmological manifestation of some types of flavivirus. Although these infections do not affect the eye commonly, this is still possible, and that is why this review is interesting. The authors have performed a deep review of these infections and it is well organized. Congratulations.

I have only a few changes I would suggest. Most of the clinical manifestations in every infection are not followed by percentages of incidence. For example, in page 5-anterior segment manifestations. I would recommend the authors to add the percentage of cases presenting each ocular manifestation, when possible. Possibly, some of them are not reported in literarure.

Author Response

We warmly and sincerely thank the reviewers for their thorough reading and comment, which will add a great value to our manuscript. Please find below a complete and point-by-point response to reviewers, with corresponding changes throughout our revised manuscript. The references were also added in the manuscript.

The authors present a review of ophthalmological manifestation of some types of flavivirus. Although these infections do not affect the eye commonly, this is still possible, and that is why this review is interesting. The authors have performed a deep review of these infections and it is well organized. Congratulations.

I have only a few changes I would suggest. Most of the clinical manifestations in every infection are not followed by percentages of incidence. For example, in page 5-anterior segment manifestations. I would recommend the authors to add the percentage of cases presenting each ocular manifestation, when possible. Possibly, some of them are not reported in literature.

We acknowledge reviewer 2's valuable suggestion and have incorporated the percentages of incidence in the manuscript, when possible.

Regarding:

· Dengue virus:

o Line 156 “In dengue related maculopathy, the prevalence of cystoid macular edema and foveolitis was evaluated to 24.6% and 33.7% respectively [40].”

o Line 173 “A study of patients (eyes,n=65) with ocular manifestations of DF reported a prevalence of retinal vasculitis in 23.1% of cases [40].”

o Line 178 “In addition to the common subconjunctival hemorrhage observed in nearly half of the patients, reported anterior segment manifestations include anterior uveitis (7.7%) [48].”

o Line 184 “The reported rate of optic neuritis ranged from 0 to 1.5% [48].”

· West nile virus:

o Line 252 “However, the reported rate of multifocal chorioretinitis varies widely in the literature, ranging from 14% to 79% [69]. There appears to be an increased prevalence of multifocal chorioretinitis associated with the presence of neurological manifestations [70].”

o Line 283 “A study of patients (n=51 eyes) with intraocular inflammation, tested positive for WNV reported vitritis (73%), papilledema (14%), intraretinal hemorrhages (43%), vasculitis (32%) and retinal occlusive vasculitis (16%) [71].”

· Yellow fever virus: Line 346 In yellow fever patients, retinopathy may occur in 20% of cases [96], which include retinal nerve fiber layer infarcts (55%), superficial hemorrhages (35%) and grayish deep lesions (30%).

· Zika virus:

o Line 410” In the acute phase, reported ophthalmological signs include non-purulent conjunctivitis (40%) and retroorbital pain (40%) [8,118,119].

o Line 421” The most common ocular signs (85%) are macular and optic nerves abnormalities [124]. “

o Line 424“Optical coherence tomography (OCT) of these lesions shows ellipsoid zone disruption (100%), retinal and choroidal thinning (respectively 89% and 78%) [127]. “

o Line 428“Anterior segment lesions include iris coloboma, corneal ectasia, lens subluxation, cataract, and congenital glaucoma (12%) [129-131]. “

· Japanese encephalitis virus: Reports of ocular manifestations are scarce, and percentage of incidence are not available.

· Kyasanur forest disease virus: Lines 549-552“Ocular manifestations are common in KFD, with rare historical studies reporting conjunctival congestion as the most frequent ocular sign (100%) [167]. Other ophthalmic features include hemorrhages in various ocular sites (conjunctiva (11%), vitreous humor (1%), retina (12%)), iritis (3%), keratitis (9%), and papilledema (1%) that may occur in encephalitic patients [167]. Lens opacification has been reported [170].”

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

The author carefully considered the points pointed out by the reviewer and made corrections and additions. It is assumed that this improvement has enabled readers to gain sufficient knowledge about the disease that the authors wanted to show. Therefore, it is considered to accept this paper in its current form.

Reviewer 2 Report

Comments and Suggestions for Authors

All the suggested changes have been performed. I congratulate the authors for this valuable deep review.